Dissertations / Theses on the topic 'Thin film silicon layers'
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1
McCann, Michelle Jane, and michelle mccann@uni-konstanz de. "Aspects of Silicon Solar Cells: Thin-Film Cells and LPCVD Silicon Nitride." The Australian National University. Faculty of Engineering and Information Technology, 2002. http://thesis.anu.edu.au./public/adt-ANU20040903.100315.
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This thesis discusses the growth of thin-film silicon layers suitable for solar cells using
liquid phase epitaxy and the behaviour of oxide LPCVD silicon nitride stacks on silicon
in a high temperature ambient.¶
The work on thin film cells is focussed on the characteristics of layers grown using liquid
phase epitaxy. The morphology resulting from different seeding patterns, the transfer of
dislocations to the epitaxial layer and the lifetime of layers grown using oxide compared
with carbonised photoresist barrier layers are discussed. The second half of this work
discusses boron doping of epitaxial layers. Simultaneous layer growth and boron doping
is demonstrated, and shown to produce a 35um thick layer with a back surface field
approximately 3.5um thick.¶
If an oxide/nitride stack is formed in the early stages of cell processing, then characteristics of the nitride may enable increased processing flexibility and hence the realisation
of novel cell structures. An oxide/nitride stack on silicon also behaves as a good anti-
reflection coating. The effects of a nitride deposited using low pressure chemical vapour
deposition on the underlying wafer are discussed. With a thin oxide layer between the
silicon and the silicon nitride, deposition is shown not to significantly alter effective life-times.¶
Heating an oxide/nitride stack on silicon is shown to result in a large drop in effective
Lifetimes. As long as at least a thin oxide is present, it is shown that a high temperature
nitrogen anneal results in a reduction in surface passivation, but does not significantly
affect bulk lifetime. The reduction in surface passivation is shown to be due to a loss of
hydrogen from the silicon/silicon oxide interface and is characterised by an increase in
Joe. Higher temperatures, thinner oxides, thinner nitrides and longer anneal times are all
shown to result in high Joe values. A hydrogen loss model is introduced to explain the
observations.¶
Various methods of hydrogen re-introduction and hence Joe recovery are then discussed
with an emphasis on high temperature forming gas anneals. The time necessary
for successful Joe recovery is shown to be primarily dependent on the nitride thickness
and on the temperature of the nitrogen anneal. With a high temperature forming gas
anneal, Joe recovery after nitrogen anneals at both 900 and 1000oC and with an optimised
anti-reflection coating is demonstrated for chemically polished wafers.¶
Finally the effects of oxide/nitride stacks and high temperature anneals in both nitrogen
and forming gas are discussed for a variety of wafers. The optimal emitter sheet
resistance is shown to be independent of nitrogen anneal temperature. With textured
wafers, recovery of Joe values after a high temperature nitrogen anneal is demonstrated
for wafers with a thick oxide, but not for wafers with a thin oxide. This is shown to be
due to a lack of surface passivation at the silicon/oxide interface.
2
Zhang, Wendi [Verfasser]. "Ion beam treatment of functional layers in thin-film silicon solar cells / Wendi Zhang." Aachen : Hochschulbibliothek der Rheinisch-Westfälischen Technischen Hochschule Aachen, 2013. http://d-nb.info/1038570891/34.
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Schillinger, Kai [Verfasser], and Harald [Akademischer Betreuer] Hillebrecht. "Crystalline silicon carbide intermediate layers for silicon thin-film solar cells = Kristalline Siliciumkarbid Zwischenschichten für Silicium Dünnschicht Solarzellen." Freiburg : Universität, 2014. http://d-nb.info/1123480354/34.
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Fu, Engang. "Study of epitaxial thin films of YBa2Cu3O7-[delta] on silicon with different buffer layers." Click to view the E-thesis via HKUTO, 2005. http://sunzi.lib.hku.hk/hkuto/record/B3637488X.
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Fu, Engang, and 付恩剛. "Study of epitaxial thin films of YBa2Cu3O7-[delta] on silicon with different buffer layers." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2005. http://hub.hku.hk/bib/B3637488X.
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Paus, K. "The electron microscopy of silicon of sapphire materials." Thesis, University of Oxford, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.382598.
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Rodriguez, Jose Virgilio Anguita. "Thin film coatings for new generation infrared thermal picture synthesising devices." Thesis, University of Surrey, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.341383.
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Zhang, Chao [Verfasser], Uwe [Akademischer Betreuer] Rau, and Miroslav [Akademischer Betreuer] Zeman. "Interface and Topography Optimization for Thin-Film Silicon Solar Cells with Doped Microcrystalline Silicon Oxide Layers / Chao Zhang ; Uwe Rau, Miroslav Zeman." Aachen : Universitätsbibliothek der RWTH Aachen, 2017. http://nbn-resolving.de/urn:nbn:de:101:1-2018071608023066276027.
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Zhang, Chao Verfasser], Uwe [Akademischer Betreuer] [Rau, and Miroslav [Akademischer Betreuer] Zeman. "Interface and Topography Optimization for Thin-Film Silicon Solar Cells with Doped Microcrystalline Silicon Oxide Layers / Chao Zhang ; Uwe Rau, Miroslav Zeman." Aachen : Universitätsbibliothek der RWTH Aachen, 2017. http://d-nb.info/1162845945/34.
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Mogilatenko, Anna. "Electron Microscopy Characterization of Manganese Silicide Layers on Silicon." Doctoral thesis, Universitätsbibliothek Chemnitz, 2003. http://nbn-resolving.de/urn:nbn:de:swb:ch1-200300523.
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The present thesis reports on the transmission electron microscopy structure characterization of semiconducting thin films of higher manganese silicides (HMS or MnSi1.7) grown on (001)Si by different UHV deposition methods (the template method, reactive deposition and surfactant mediated reactive deposition). In this work electron diffraction technique was applied for the fist time to reveal the HMS phase growing in thin MnSi1.7 films. The obtained results suggest the presence of the shortest in c-axis length HMS phase, namely Mn4Si7, within our experiments. It has been shown that growth of epitaxial Mn4Si7 grains can be achieved by the template technique. In particular, the influence of the template thickness on the silicide layer quality has been investigated. It has been found that deposition of a thin Mn layer of 0.8 nm nominal thickness at room temperature prior to the Mn/Si codeposition at 550°C causes the formation of a silicide template that leads to the preferred epitaxial Mn4Si7 growth with (110)[4-41]Mn4Si7 || (001)[110]Si. Silicide crystallites of two additional orientation relations, (3-38)[-443]Mn4Si7 || (001)[110]Si and (001)[110] Mn4Si7 || (001)[110]Si, were present at the same template thickness to a lesser extent. Due to the crystal symmetry of Mn4Si7 and Si the epitaxial Mn4Si7 growth on (001)Si leads to the formation of a number of Mn4Si7 domains for each observed orientation. Additional experiments were carried out using the reactive deposition process. It has been shown that the deposition of Mn onto (001)Si at substrate temperatures higher then 600°C leads to the formation of large silicide islands growing with the major part of their elongated grains parallel to <110>Si. XRD investigations show the observed silicide grains to exhibit the following texture: (110)Mn4Si7 || (001)Si. The found island morphology of Mn4Si7 films can be modified by the deposition of about one monolayer of Sb (surfactant) onto (001)Si prior to the Mn-deposition. This process results in an increase of the silicide island density by about two orders of magnitude and decrease of the silicide grain dimensions to nanometer range. Furthermore, in the presence of Sb the silicide layers grow with the preferential orientation: (100)[010]Mn4Si7 || (001)[100]Si. The observed changes in the morphology and orientation of the Mn4Si7 layers can be explained by the reduced diffusion of Mn and Si atoms in the presence of the Sb overlayerIn der vorliegenden Arbeit wird die Struktur von dünnen MnSi1.7-Schichten, die mit verschiedenen UHV-Herstellungsmethoden (template-Verfahren, reaktive Abscheidung und surfactant gesteuerte Abscheidung) auf (001)Si hergestellt wurden, mittels Elektronenmikroskopie charakterisiert. Die Ergebnisse der Elektronenbeugung an dünnen Mangansilicid-Schichten können vollständig interpretiert werden, wenn von den bekannten höheren Mangansiliciden (HMS) das Mn4Si7 als einzige vorliegende Phase angenommen wird. Der Hauptteil der Arbeit beschäftigt sich mit den mittels template-Verfahren abgeschiedenen Mn4Si7-Schichten. In diesen Experimenten wurde der Einfluss der template-Dicke auf die Morphologie und Orientierung der hergestellten Schichten untersucht. Es wird gezeigt, dass bei der Abscheidung von einer dünnen Mn-Schicht mit einer nominalen Dicke von 0,8 nm bei Raumtemperatur und weiterer Mn/Si-Koabscheidung bei einer Substrattemperatur von 550°C nahezu geschlossene Silicidschichten mit der bevorzugten Orientierungsbeziehung (110)[4-41]Mn4Si7 || (001)[110]Si entstehen. Weiterhin wachsen bei dieser template-Dicke Mn4Si7-Kristallite mit den Orientierungsbeziehungen: (3-38)[-443]Mn4Si7 || (001)[110]Si und (001)[110] Mn4Si7 || (001)[110]Si. Bei jeder gefundenen Orientierungsbeziehung treten beim Wachstum von Mn4Si7 auf (001)Si mehrere Domäne auf. Zusätzliche Experimente wurden unter Verwendung der reaktiven Schichtabscheidung durchgeführt. Sie verdeutlichen, dass bei reaktiver Abscheidung von Mn auf (001)Si ab einer Substrattemperatur von 600°C ein Wachstum von Mn4Si7-Inseln entlang den [110]-Richtungen des Siliciums erfolgt. XRD-Untersuchungen zeigen, dass diese Inseln die folgende Textur haben: (110)Mn4Si7 || (001)Si. Durch eine Modifizierung der Si-Oberfläche mit einer bis zu einer Monolage dicken Sb-Schicht (surfactant) kann das Mn4Si7-Inselwachstum beeinflusst werden. Die dabei gefundene Erhöhung der Mn4Si7-Inseldichte wird hier auf die reduzierte Mn- und Si-Diffusion zurükgeführt. Weiterhin wurde gefunden, dass dieser Abscheidungsprozess Mn4Si7-Kristallite der bevorzugten Orientierung (100)[010]Mn4Si7 || (001)[110]Si liefert
11
Fallon, Jason Michael. "The structure and properties of interface regions in nanostructured Co/Si thin films." Thesis, University of Salford, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.301415.
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Doucette, Luke D. "Use of an Epitaxial BaFz Buffer Layer on Silicon to Control W03 Thin Film Growth." Fogler Library, University of Maine, 2002. http://www.library.umaine.edu/theses/pdf/DoucetteLD2002.pdf.
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Corpus, Mendoza Asiel Neftali. "Influence of the p-type layer on the performance and stability of thin film silicon solar cells." Thesis, University of Sheffield, 2017. http://etheses.whiterose.ac.uk/16581/.
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The poor lateral conductance of amorphous silicon necessitates the use of a contact covering the entire surface of thin film silicon solar cells to minimise the resistance. This contact must be highly conductive, as well as transparent to allow absorption of light in the inner layers. In recent years this has paved way for transparent conducting oxides (TCOs) to be used in solar technology. However, the absence of a p-type TCO complicates the fabrication of an Ohmic contact to a-Si:H(p). Moreover, the difference in bandgap between the two materials results in a Schottky interface which has not been investigated comprehensively in terms of on-state/optical performance and stability before. This thesis describes the physics of thin film silicon solar cells and their Schottky interface with zinc oxide (ZnO). Here, current-voltage-temperature (I-V-T) measurements and computer simulations are used in order to evaluate the Schottky barrier height of ZnO/a-Si:H(p) and ZnO/μc-Si:H(p) heterojunctions. It is observed that a high doping concentration of the p-layer can reduce the effective Schottky barrier height by increasing the tunnelling transport mechanism at the interface. The same heterojunctions are also tested in ZnO/p-layer/a-Si:H(i)/a-Si:H(n)/ZnO/Ag solar cells. It is found that despite the superior electrical properties of the ZnO/μc-Si:H(p) contact compared to the ZnO/a-Si:H contact, an improved performance is observed in cells using the latter. This contradictory result is explained by a misalignment of the energy bands at the μc-Si:H(p)/a-Si:H(i) interface. This reduces the open circuit voltage (VOC) of the cell in comparison to the a-Si:H(p)/a-Si:H(i) structure. These results lead to the theory behind optimization of a mixed μc-Si:H(p)/a-Si:H(p) window layer that can overcome the Schottky interface without compromising the p-layer/a-Si:H(i) interface. Further, the conventional equivalent electronic circuit of a solar cell is expanded with a Schottky diode in series that represents the non-ideal contact. The analysis of this equivalent circuit shows that non-ideal metal/semiconductor contacts for solar cells can be approximated as Ohmic when they show a Schottky barrier lower than 0.5 eV. Also, the same model allows to distinguish the sections of the cell that degrade during light exposure and current injection. It is observed that all of the solar cells analysed here show a reduction of their VOC, short circuit current (JSC) and fill factor (FF) as a function of time when soaked with 1 Sun light, whereas the fully a-Si:H solar cells show a simultaneous increase of VOC, a decrease of FF, and a minimal decrease of JSC as a function of time when injected with a constant current of 10 mA in the dark. Increase in recombination in the absorption layer of the cell during light exposure can be detected by an increase of the ideality factor (m) of the main junction. On the other hand, the ideality factor (n) of the Schottky junction decreases after current injection. This indicates a detrimental effect on the tunnelling transport mechanism at the contact. Computer simulations reveal that the decrease of n is the result of a change in the a-Si:H(p) hole concentration and doping profile due to the excess of electrons injected during stress. This degradation of the Schottky interface is not observed when μc-Si:H(p) is used as the p-layer. This thesis demonstrates that a complete understanding of degradation of the I-V characteristics of an a-Si:H solar cell can only be achieved when all transport mechanisms of a Schottky contact are considered.
14
Becker, Jan-Philipp [Verfasser], Uwe [Akademischer Betreuer] Rau, and Gunther [Akademischer Betreuer] Wittstock. "Electrochemical Texturing and Deposition of Transparent Conductive Oxide Layers for the Application in Silicon Thin-Film Solar Cells / Jan-Philipp Becker ; Uwe Rau, Gunther Wittstock." Aachen : Universitätsbibliothek der RWTH Aachen, 2015. http://d-nb.info/1126729671/34.
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Coathup, David James. "The effect of interface layers and doping on the multiferroic properties of bismuth titanate oxide thin films on silicon." Thesis, Aston University, 2017. http://publications.aston.ac.uk/38210/.
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For the development of magnetoelectric memory devices, the development of artificial magnetoelectric materials is necessary. Previous work in the field had focused on the multiferroic properties of this material in bulk form, however, for a practical device, a thin film investigation is needed. This thesis details the author's investigation into the multiferroic properties of bismuth titanate oxide, Bi4Th012, (BTO) thin films doped with lanthanum, niobium, iron and cobalt, to form the novel material Bi3.2slao.7sLTb.sNbo.2sFeo.mCoo.m012 (BTFC), and how different interface layers influence their structural and electronic properties when they are deposited on silicon substrates. The aim of this research is to achieve a multiferroic BTO thin film with strong ferroelectric and ferromagnetic properties by utilising a novel combination of dopants. Chapter 1is the introduction, providing insight into the layout and structure of the thesis making it easier for the reader to follow. Chapter 2 is the background literature review, which discusses the real life industrial demands of this work, and is followed by a discussion of the physics and material science principles behind this investigation. Chapter 3 is the experimental literature review, in which the material synthesis, device fabrication and characterisation techniques utilised in this work are discussed. The experimental chapters begins with Chapter 4, in which the effect of a zinc oxide (ZnO) interface layer on crystalline properties of BTFC on silicon is investigated. Chapter 5 follows this investigation up by investigating ferroelectric propertied of BTFC thin films on silicon with ZnO interface layers. Finally chapter 6 looks at BTFC thin films on silicon substrates with platinum interface layers, and both simultaneous ferroelectric and ferromagnetic properties were present, confirming multiferroic behaviour. Initial investigations into the deposition onto silicon were unsuccessful, but were overcome by utilising ZnO interface layers. The ZnO interface layer eliminated some critical difficulties; however high resolution transmission electron microscopy (HRTEM) analysis showed zinc atoms from inside the interface layer diffusing into the BTFC thin film. The investigation into the ferroelectric properties of thin films using the triangular voltage waveform method confirmed ferroelectric domain switching, but were inhibited by the need for a vacuum annealing environment to prevent the oxidation of the silicon substrate. This resulted in the generation of oxygen vacancies within the BTFC thin film, which limited driving voltage during the measurement, presenting ferroelectric saturation. The final investigation was focused on BTFC deposited on platinised-silicon substrates. Platinum is proved to be the superior interface layer, due to its chemical and thermal stability. The investigation found high quality crystalline BTFC, with a high dielectric constant and leakage current, which can be attributed to the doping effect. The ferroelectric measurements demonstrated a fully saturated ferroelectric loop, and a remnant polarisation and coercivity of 2Pr = 11.03!lC/cm 2, and 2Ec = 196.5kV/em on the optimised thin films. Ferromagnetic measurements of the sample were challenging, due to the small total magnetisation of the thin film resulting from its low volume and mass. Using a Superconducting Quantum User Interface Device {SQUID) vibrating sample microscopy {VSM), Ferromagnetisum was presented in the bulk and thin film form, however, the remnant magnetisation of the thin film could not be determined, due to its noise level value. This discovery proves the existence of simultaneous ferroelectric and ferromagnetic phases in BTFC thin film, confirming muitiferroic behaviour of the deposited thin films had been achieved with the chosen dopants.
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Zai, Marvin Ho-Ming. "Chemical synthesis of lead zirconate titanate thin films for a piezoelectric actuator." Thesis, Imperial College London, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.367760.
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Gasparetto, Jacopo. "Investigation of indium tin oxide-titanium dioxide interconnection layers for perovskite-silicon tandem solar cells." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2017. http://amslaurea.unibo.it/14230/.
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Per superare i limiti di efficienza delle tradizionali celle al silicio, dovuti alla termalizzazione degli elettroni generati dai fotoni solari più energetici, la comunità scientifica si è recentemente indirizzata verso la tecnologia di celle tandem monolitiche perovskite-silicio. In questo tipo di dispositivi, una cella perovskite viene depositata direttamente su di una cella etero-giunzione al silicio (SHJ) ad alta efficienza e, grazie al suo band gap, assorbe i fotoni più energetici permettendo un efficienza totale maggiore. Le celle perovskite attualmente in fase di studio presso Fraunhofer ISE possiedono un contatto posteriore formato da diossido di titanio (TiO2), mentre il contatto frontale delle celle SHJ è formato tipicamente di indium tin oxide (ITO). In questo lavoro si è studiata la fattibilità di celle solari tandem perovskite-silicio, analizzando dettagliatamente l’interfaccia ITO/TiO2 e la sua resistività. Poiché la resistenza di serie di una cella fotovoltaica, di qualunque natura, è un parametro fortemente limitate per l’efficienza di conversione, è necessario che questi layer di interconnessione abbiano una resistenza più bassa possibile per non causare perdite dovute al trasporto dei portatori di carica. Sono stati preparati campioni con formati da uno stack ITO/TiO2/ITO depositato su un substrato di silicio. Tutti i layer di ITO sono stati depositati tramite sputtering mentre sono state testate tre differenti tecniche di deposizione per il TiO2: Electron Beam Physical Vapour Deposition (EBPVD), Thermal Atomic Layer Deposition (T-ALD) e Plasma Enhanced ALD (PE-ALD). Per ogni tecnica di deposizione del TiO2 si è studiata la resistenza dei film, anche in seguito a trattamenti termici a differenti condizioni. Sono state inoltre condotte analisi di diffrazione a raggi X (XRD) e spettroscopia fotoelettronica a raggi X (XPS) per sondare la struttura cristallina e la composizione chimica dei layer di TiO2 depositati su ITO tramite le differenti tecniche.
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Grasby, Timothy John. "Growth techniques and characterisation of Siâ†1â†-â†xGeâ†x heterostructures for pMOS applications." Thesis, University of Warwick, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.365234.
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Kotsedi, Lebogang. "Fabrication and characterization of a solar cell using an aluminium p-doped layer in the hot-wire chemical vapour deposition process." Thesis, University of the Western Cape, 2010. http://etd.uwc.ac.za/index.php?module=etd&action=viewtitle&id=gen8Srv25Nme4_1349_1363785866.
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When the amorphous silicon (a-Si) dangling bonds are bonded to hydrogen the concentration of the dangling bond is decreased. The resulting film is called hydrogenated amorphous silicon (a-Si:H). The reduction in the dangling bonds concentration improves the optoelectrical properties of the film. The improved properties of a-Si:H makes it possible to manufacture electronic devices including a solar cell. A solar cell device based on the hydrogenated amorphous silicon (a-Si:H) was fabricated using the Hot-Wire Chemical Vapour Deposition (HWCVD). When an n-i-p solar cell configuration is grown, the norm is that the p-doped layer is deposited from a mixture of silane (SiH4) gas with diborane (B2H6). The boron atoms from diborane bonds to the silicon atoms and because of the number of the valance electrons, the grown film becomes a p-type film. Aluminium is a group 3B element and has the same valence electrons as boron, hence it will also produce a p-type film when it bonds with silicon. In this study the p-doped layer is grown from the co-deposition of a-Si:H from SiH4 with aluminium evaporation resulting in a crystallized, p-doped thin film. When this thin film is used in the n-i-p cell configuration, the device shows photo-voltaic activity. The intrinsic layer and the n-type layers for the solar cell were grown from SiH4 gas and Phosphine (PH3) gas diluted in SiH4 respectively. The individual layers of the solar cell device were characterized for both their optical and electrical properties. This was done using a variety of experimental techniques. The analyzed results from the characterization techniques showed the films to be of device quality standard. The analysed results of the ptype layer grown from aluminium showed the film to be successfully crystallized and doped. A fully functional solar cell was fabricated from these layers and the cell showed photovoltaic activity.
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Michard, Stephan Yann [Verfasser], Uwe [Akademischer Betreuer] Rau, and Joachim [Akademischer Betreuer] Knoch. "Relation between growth rate, material quality, and device grade condition for intrinsic microcrystalline silicon : from layer investigation to the application to thin-film tandem solar cells / Stephan Yann Michard ; Uwe Rau, Joachim Knoch." Aachen : Universitätsbibliothek der RWTH Aachen, 2015. http://nbn-resolving.de/urn:nbn:de:hbz:82-rwth-2015-012581.
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Michard, Stephan Yann Verfasser], Uwe [Akademischer Betreuer] [Rau, and Joachim [Akademischer Betreuer] Knoch. "Relation between growth rate, material quality, and device grade condition for intrinsic microcrystalline silicon : from layer investigation to the application to thin-film tandem solar cells / Stephan Yann Michard ; Uwe Rau, Joachim Knoch." Aachen : Universitätsbibliothek der RWTH Aachen, 2015. http://d-nb.info/1127739654/34.
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Panda, Durga Prasanna. "Nanocrystalline silicon thin film transistors." [Ames, Iowa : Iowa State University], 2006.
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Bauza, M. "Nanocrystalline silicon thin film transistors." Thesis, University College London (University of London), 2013. http://discovery.ucl.ac.uk/1385744/.
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This thesis presents my work on the fabrication of nanocrystalline silicon (nc-Si) thin film transistors and characterization of their stability under different conditions. Nc-Si transistors are promising alternative to the current amorphous silicon (a-Si:H) devices, especially in areas where a-Si:H TFTs are reaching the performance ceiling, e.g. new large area applications such as active matrix organic light emitting diode displays (AMOLED). This is mostly due to the superior nc-Si properties – high carrier mobility and good electrical stability stemming from the crystalline Si grains embedded in a disordered a-Si:H matrix. Another large advantage of nc-Si TFTs over competing materials is the full compatibility with the a-Si:H fabrication base. Nanocrystalline silicon is a relatively new material and some aspects require further investigation before industrial applications. The pool of knowledge on nc-Si devices is especially shallow for the electrical stability of bottom gate TFTs under prolonged illumination which is important for several thin film applications, such as AMOLED and phototransistors. This issue was selected as the main topic of the thesis. Top gate TFTs were also designed, fabricated, characterized and compared to the bottom gate transistors. The electrically detected magnetic resonance method was employed to investigate the nc-Si/dielectric structures and it was shown that it can be used to evaluate the TG TFT channel/dielectric interface.
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Stragier, Anne-Sophie. "Elaboration et caractérisation de structures Silicium-sur-Isolant réalisées par la technologie Smart Cut™ avec une couche fragile enterrée en silicium poreux." Thesis, Lyon, INSA, 2011. http://www.theses.fr/2011ISAL0108.
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Au vu des limitations rencontrées par la miniaturisation des circuits microélectroniques, l’augmentation de performances des systèmes repose largement aujourd’hui sur la fabrication d’empilements de couches minces complexes et innovants pour offrir davantage de compacité et de flexibilité. L’intérêt grandissant pour la réalisation de structures innovantes temporaires, i.e. permettant de réaliser des circuits sur les deux faces d’un même film, nous a mené à évaluer les potentialités d’une technologie combinant le transfert de films minces monocristallins, i.e. la technologie Smart Cut™, et un procédé de de porosification partielle du silicium afin de mettre au point une technologie de double report de film monocristallin. En ce sens, des substrats de silicium monocristallin ont été partiellement porosifiés par anodisation électrochimique. La mise en œuvre de traitements de substrats partiellement poreux a nécessité l’emploi de techniques de caractérisation variées pour dresser une fiche d’identité des couches minces poreuses après anodisation et évaluer l’évolution des propriétés de ces couches en fonction des différents traitements appliqués. Les propriétés chimiques, structurales et mécaniques des couches de Si poreux ont ainsi été étudiées via l’utilisation de différentes techniques de caractérisation (XPS-SIMS, AFM-MEB-XRD, nanoindentation, technique d’insertion de lame, etc.). Ces études ont permis d’appréhender et de décrire les mécanismes physiques mis au jeu au cours des différents traitements et de déterminer les caractéristiques {porosité, épaisseur} optimales des couches poreuses compatibles avec les séquences de la technologie proposée. La technologie Smart Cut™ a ainsi été appliquée à des substrats partiellement porosifiés menant à la fabrication réussie d’une structure temporaire de type Silicium-sur-Isolant avec une couche de silicium poreux enterrée. Ces structures temporaires ont été « démontées » dans un second temps par collage polymère ou collage direct et insertion de lame menant au second report de film mince monocristallin par rupture au sein de la couche porosifiée et donc fragile. Les structures fabriquées ont été caractérisées pour vérifier leur intégrité et leurs stabilités chimique et mécanique. Les propriétés cristallines du film mince de Si monocristallin, reporté en deux temps, ont été vérifiées confirmant ainsi la compatibilité des structures fabriquées avec des applications microélectroniques telles que les applications de type « Back-Side Imager » nécessitant une implémentation de composants sur les deux faces du film. Ainsi une technologie prometteuse et performante a pu être élaborée permettant le double report de films minces monocristallins et à fort potentiel pour des applications variées comme les imageurs visibles ou le photovoltaïqueAs scaling of microelectronic devices is confronted from now to fundamental limits, improving microelectronic systems performances is largely based nowadays on complex and innovative stack realization to offer more compaction and flexibility to structures. Growing interest in the fabrication of innovative temporary structures, allowing for example double sided layer processing, lead us to investigate the capability to combine one technology of thin single crystalline layer transfer, i.e. the Smart Cut™ technology, and partial porosification of silicon substrate in order to develop an original double layer transfer technology of thin single crystalline silicon film. To this purpose, single crystalline silicon substrates were first partially porosified by electrochemical anodization. Application of suitable treatments of porous silicon layer has required the use of several characterization methods to identify intrinsic porous silicon properties after anodization and to verify their evolution as function of different applied treatments. Chemical, structural and mechanical properties of porous silicon layers were studied by using different characterization techniques (XPS-SIMS, AFM-MEB-XRD, nanoindentation, razor blade insertion, etc.). Such studies allowed comprehending and describing physical mechanisms occurring during each applied technological steps and well determining appropriated {porosity, thickness} parameters of porous silicon layer with the developed technological process flow. The Smart Cut™ technology was successfully applied to partially porosified silicon substrates leading to the fabrication of temporary SOI-like structures with a weak embedded porous Si layer. Such structures were then “dismantled” thanks to a second polymer or direct bonding and razor blade insertion to produce a mechanical rupture through the fragile embedded porous silicon layer and to get the second thin silicon film transfer. Each fabricated structure was characterized step by step to check its integrity and its chemical and mechanical stabilities. Crystalline properties of the double transferred silicon layer were verified demonstrating the compatibility of such structures with microelectronic applications such as “Back-Side Imagers” needing double-sided layer processing. Eventually, a promising and efficient technology has been developed to allow the double transfer of thin single crystalline silicon layer which presents a high potential for various applications such as visible imagers or photovoltaic systems
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Bozeat, Robert John. "Thin film optical waveguides on silicon." Thesis, University of Nottingham, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.320551.
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Ariel, Nava. "Integrated thin film batteries on silicon." Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/33612.
Full textAbstract:
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2005.Includes bibliographical references (p. 147-158).
Monolithic integration has been implemented successfully in complementary metal oxide semiconductor (CMOS) technology and led to improved device performance, increased reliability, and overall cost reduction. The next element to be incorporated on the silicon chip is the power unit; possibly as part of the back end process of the very large scale integrated (VLSI) circuits' production. This thesis describes the work done in developing and studying thin film integrated lithium ion batteries compatible with microelectronics with respect to the material system employed, the cells' fabrication methods, and performance. The project consisted of three stages; first, a material system new to the battery application field was explored and power cells were fabricated and characterized. In the second stage, the fabrication process of the first material system cells was optimized thereby improving their performance. The third stage dealt with a more conventional battery material system, utilizing thin film technology to fabricate and explore power cells.
(cont.) All the cells fabricated in this work were created using microelectronic technology and were characterized by thin film analysis techniques and by measurement equipment commonly used for microelectronic device testing. The cells were fabricated in four sizes of active areas: 5x5 mm², 2x2 mm², lxl mm², and 0.5x0.5 mm². The first material system consisted of a novel lithium-free electrolyte in the form of an ultra-thin SiO₂ layer, thermally grown from sacrificial polysilicon layer on a doped polysilicon anode. The concept of SiO₂ as an electrolyte is innovative since common solid state lithium and lithium ion batteries consist of 1-2 ptm thick lithium-containing electrolytes. The controlled transport of lithium through SiO₂, 9-40 nm thick, was studied for electrolyte application. The fabricated LiCoO₂/SiO₂/polysilicon cells were successfully charged and discharged. This stage of the project demonstrated the concept of an ultra-thin lithium free electrolyte layer and introduces SiO₂ as an interesting candidate material. The second stage of the project focused on improving the LiCoO₂/SiO₂/polysilicon cell's performance and optimizing its fabrication process.
(cont.) Chemical mechanical polishing (CMP), a typical planarization method in microelectronics, new to the battery application field, was introduced in order to enhance the cell's properties and performance. LiCoO₂/SiO₂/polysilicon cells consisting of Si0₂ layers 7-40 nm thick were studied. Cells with the planarized polysilicon anode were characterized and the planarization effect was evaluated. This stage demonstrates the importance of interfacial quality in thin film batteries and the advantages incorporation of CMP as a planarization step in the fabrication process. Finally, the third stage of the project focused on applying the thin film technology knowledge and expertise to a more commonly used material system V₂0₅/LiPON/LiCoO₂. With the aim of reducing interfacial roughness, a surface morphology study of V₂0₅ was performed, tailoring different deposition conditions and surface morphology. Implementing the optimized conditions obtained from this analysis, a V₂0₅/LiPON/LiCoO₂ rocking-chair battery was studied next. The cells consisted of approximately 100 or 350 nm thick lithium phosphorus oxynitride (LiPON) electrolyte.
(cont.) This stage demonstrated the advantage of thin film technology in reducing film thickness and the performance enhancement achieved. The work described in this thesis approached the thin film battery subject from the microelectronic perspective, in order to "bring the battery into the clean room".
by Nava Ariel.
Ph.D.
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Lo, Hsi-Wen Tai Yu-Chong Tai Yu-Chong. "Thin film silicon for implantable electronics /." Diss., Pasadena, Calif. : California Institute of Technology, 2009. http://resolver.caltech.edu/CaltechETD:etd-09242008-151715.
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Inns, Daniel Photovoltaics & Renewable Energy Engineering Faculty of Engineering UNSW. "ALICIA polycrystalline silicon thin-film solar cells." Publisher:University of New South Wales. Photovoltaics & Renewable Energy Engineering, 2007. http://handle.unsw.edu.au/1959.4/43600.
Full textAbstract:
Thin-film silicon photovoltaics are seen as a good possibility for reducing the cost of solar electricity. The focus of this thesis is the ALICIA cell, a thin-film polycrystalline silicon solar cell made on a glass superstrate. The name ALICIA comes from the fabrication steps - ALuminium Induced Crystallisation, Ion Assisted deposition. The concept is to form a high-quality crystalline silicon layer on glass by Aluminium Induced Crystallisation (AIC). This is then the template from which to epitaxially grow the solar cell structure by Ion Assisted Deposition (IAD). IAD allows high-rate silicon epitaxy at low temperatures compatible with glass. In thin-film solar cells, light trapping is critical to increase the absorption of the solar spectrum. ALICIA cells have been fabricated on textured glass sheets, increasing light absorption due to their anti-reflection nature and light trapping properties. A 1.8 μm thick textured ALICIA cell absorbs 55% of the AM1.5G spectrum without a back-surface reflector, or 76% with an optimal reflector. Experimentally, Pigmented Diffuse Reflectors (PDRs) have been shown to be the best reflector. These highly reflective and optically diffuse materials increase the light-trapping potential and hence the short-circuit currents of ALICIA cells. In textured cells, the current increased by almost 30% compared to using a simple aluminium reflector. Current densities up to 13.7 mA/cm2 were achieved by application of a PDR to the best ALICIA cells. The electronic quality of the absorber layer of ALICIA cells is strongly determined by the epitaxy process. Very high-rate epitaxial growth decreases the crystalline quality of the epitaxial layer, but nevertheless increases the short-circuit current density of the solar cells. This indicates that the diffusion length in the absorber layer of the ALICIA cell is primarily limited by contamination, not crystal quality. Further gains in current density can therefore be achieved by increasing the deposition rate of the absorber layer, or by improving the vacuum quality. Large-area ALICIA cells were then fabricated, and series resistance reduced by using an interdigitated metallisation scheme. The best measured efficiency was 2.65%, with considerable efficiency gains still possible from optimisation of the epitaxial growth and metallisation processes.
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Lau, S. P. "Thin film silicon carbide for electroluminescent devices." Thesis, Swansea University, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.637853.
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In this research, the optoelectronic and structural properties of thin film silicon carbide (SiC) prepared by plasma enhanced chemical vapour deposition and excimer (ArF) laser crystallisation are presented. These materials have been utilised as p-i-n electroluminescent devices, including development of various novel device structures. A wide-ranging series of experiments aimed at optimising the deposition conditions of amorphous and microcrystalline SiC films are described. Dark conductivity, photoconductivity, photoluminescence, optical absorption by Swanepoel's method and constant photocurrent method (CPM), scanning and transmission electron microscopy, infrared spectroscopy, and elastic recoil detection analysis were employed to characterise the films. Absorption spectra and the density of states profile of amorphous silicon carbide as found by CPM are reported. As the carbon content increases, the valence band tail becomes broader. At the same time, the deep defect density of states increases and also becomes broader. The CPM data also verified that the band gap widening is due to the conduction band shifting with increasing carbon content. It is shown that H2 dilution leads to an improvement of electronic properties via a decrease in the density of localised states. A novel method has been developed to prepare highly conductive and wide band gap doped microcrystalline silicon carbide (μc-SiC) by excimer (ArF) laser crystallisation. After crystallisation, this material has Tauc gap of around 2.0 eV and exhibits a dark conductivity as high as 20 (Ωcm)-1, more than ten orders of magnitude higher than before the laser irradiation. This is shown to be mainly correlated to structural change. The dopant concentration plays a dominant role in the electrical transport properties of μc-SiC, regardless of type of dopant and carbon concentration up to 30 at.%. Laser crystallised μc-SiC can be utilised not only as the carrier injection layer in a-SiC:H based electroluminescent devices, but also as a luminescent layer. EL devices fabricated with μc-SiC as a hole injector possess the highest electroluminescent intensity, the most stable emission and the longest operating life-time among all the investigated device structures. The electroluminescence from these devices is possibly related to the formation of some form of porous SiC by laser crystallisation.
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Aschenbeck, Jens. "Novel amorphous silicon thin film transistor structures." Thesis, University of Cambridge, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.620172.
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Dobarco-Otero, Jose. "Second-Surface Mirror Effects in Thin-Film Absorber Layers." Thesis, Virginia Tech, 2000. http://hdl.handle.net/10919/35010.
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The Thermal Radiation Group at Virginia Polytechnic Institute and State University has been developing analytical and numerical heat transfer models for NASA's Langley Research Center for more than 25 years. Recent versions of these models are being used in the design of the next-generation thermal radiation detectors intended for Earth radiation budget campaigns. The current investigation presents three models for the absorption of electromagnetic radiation in thin films. The first assumes a surface heating boundary condition. The second model, derived from electromagnetic theory, is an analytical volumetric heat generation model. This model can be applied to a semi-infinite medium or to a thin-film absorber layers behaving as a second-surface mirror; that is, a semi-transparent coating deposited on top of a reflective surface. The third model is a statistical volumetric heat generation model that is derived using the Monte Carlo ray-trace (MCRT) method. These models are compared by using them to predict the transient temperature response of a generic thermal radiation detector. Results are presented for absorber layers in which the index of refraction is equal to the extinction coefficient. It was found that both of the volumetric heat generation models produce identical results. It was also found that the response of the detector due to shorter wavelengths deviates less from the surface absorption model than at longer wavelengths. A second-surface mirror reflection model for the absorber layer of the thermal radiation detector is also presented in this thesis.Master of Science
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Hepburn, A. R. "Charge trapping instabilities in amorphous silicon/silicon nitride thin film transistors." Thesis, Open University, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.381605.
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Nominanda, Helinda. "Amorphous silicon thin film transistor as nonvolatile device." Texas A&M University, 2008. http://hdl.handle.net/1969.1/86004.
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n-channel and p-channel amorphous-silicon thin-film transistors (a-Si:H TFTs)
with copper electrodes prepared by a novel plasma etching process have been fabricated
and studied. Their characteristics are similar to those of TFTs with molybdenum
electrodes. The reliability was examined by extended high-temperature annealing and
gate-bias stress. High-performance CMOS-type a-Si:H TFTs can be fabricated with this
plasma etching method.
Electrical characteristics of a-Si:H TFTs after Co-60 irradiation and at different
experimental stages have been measured. The gamma-ray irradiation damaged bulk
films and interfaces and caused the shift of the transfer characteristics to the positive
voltage direction. The field effect mobility, on/off current ratio, and interface state
density of the TFTs were deteriorated by the irradiation process. Thermal annealing
almost restored the original state's characteristics.
Floating gate n-channel a-Si:H TFT nonvolatile memory device with a thin a-
Si:H layer embedded in the SiNx gate dielectric layer has been prepared and studied. The
hysteresis of the TFT's transfer characteristics has been used to demonstrate its memory function. A steady threshold voltage change between the "0" and "1" states and a large
charge retention time of > 3600 s with the "write" and "erase" gap of 0.5 V have been
detected. Charge storage is related to properties of the embedded a-Si:H layer and its
interfaces in the gate dielectric structure. Discharge efficiencies with various methods,
i.e., thermal annealing, negative gate bias, and light exposure, separately, were
investigated. The charge storage and discharge efficiency decrease with the increase of
the drain voltage under a dynamic operation condition. Optimum operating temperatures
are low temperature for storage and higher temperature for discharge.
a-Si:H metal insulator semiconductor (MIS) capacitor with a thin a-Si:H film
embedded in the silicon nitride gate dielectric stack has been characterized for memory
functions. The hysteresis of the capacitor's current-voltage and capacitance-voltage
curves showed strong charge trapping and detrapping phenomena. The 9 nm embedded
a-Si:H layer had a charge storage capacity six times that of the capacitor without the
embedded layer. The nonvolatile memory device has potential for low temperature
circuit applications.
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Malape, Maibi Aaron. "Low temperature growth of Amorphous Silicon thin film." Thesis, University of the Western Cape, 2007. http://etd.uwc.ac.za/index.php?module=etd&action=viewtitle&id=gen8Srv25Nme4_7768_1254727160.
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The growth of amorphous hydrogenated silicon (a-Si:H) thin films deposided by hot wire chemical vapor deposition (HWCVD) has been studied. The films have been characterised for optical and structural properties by means of UV/VIS,FITR,ERDA, XRD.XTEM and Raman spectroscopy. Low subtrate heater temperatures in the range form 130 to 200 degrees celcius were used in this thesis because it is believed to allow for the deposition of device quality a-Si:H which can be used for electronic photovoltaic devices. Furthermore, low temperatures allows the deposition of a-Si:H on any subtrate and thus offers the possibility of making large area devices on flexible organic substances. We showed that the optical and structural properties of grown a-Si:H films depended critically upon whether the films were produced with silane gas or silane diluted with hydrogen gas. We also showed that it is possible to to deposit crystalline materials at low temperature under high hydrogen dilution ratio of silane gas.
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Song, Yang Photovoltaics & Renewable Energy Engineering Faculty of Engineering UNSW. "Dielectric thin film applications for silicon solar cells." Publisher:University of New South Wales. Photovoltaics & Renewable Energy Engineering, 2009. http://handle.unsw.edu.au/1959.4/44486.
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Dielectric thin films have a long history in silicon photovoltaics. Due to the specific physical properties, they can function as passivation layer in solar cells. Also, they can be used as antireflection coating layers on top of the devices. They can improve the back surface reflectance if proper dielectric layers combination is used. What??s more, they can protect areas by masking during chemical etching, diffusion, metallization among the whole fabrication process. Crystalline silicon solar cell can be passivated by two ways: one is to deposit dielectric thin films to saturate the dangling bonds; the other is to introduce surface electrical field and repel back the minority carriers. This thesis explores thermally grown SiO2 and sputtered Si3N4(:H) to passivate n-type and thermal evaporation AlF3 to passivate p-type Float Zone silicon wafers, respectively. Sputtering is a cheap passivation method to replace PECVD in industry usage, but all sputtered samples are more likely to have encountered surface damage from neutral Ar and secondary electrons, both coming from the sputtered target. AlF3/SiO2 multi-layer stack is a negative charge combination; p inversion layer will form on the wafer surface. Light trapping is an important part in solar cell research work. In order to enhance the reflectance and improve the absorption possibility of near infrared photons, especially for high efficiency PERL cell application, the back surface structure is optimized in this work. Results show SiO2/Ag is a very good choice to replace SiO2/Al back reflectors. The maximum back surface reflectance is 97.82%. At the same time, SiO2/Ag has excellent internal angle dependence of reflectance, which is beneficial for surface textured cells. A ZnS/MgF2/SiO2/Al(Ag) superlattice can improve the back reflectance, but it is sensitive to incident angle inside the silicon wafer. If planar wafers are used to investigate all kinds of back reflectors, and an 8 degrees incident angle is fixed for typical spectrometry measurement, the results are easy to predict by Wvase software simulation. If a textured surface is considered, the light path inside the silicon wafer is very complicated and hard to calculate and simulate. The best way to evaluate the result is through experiment.
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Olding, Timothy Russell. "A thin film piezoelectric transformer for silicon integration." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape9/PQDD_0005/MQ42673.pdf.
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Milne, Stuart Brian. "Thin-film silicon based MEMS actuators and materials." Thesis, University of Cambridge, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.609898.
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Liu, Jie-Ru, and 劉杰儒. "Superlattice intrinsic layers of silicon thin-film solar cells." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/12040067480239355401.
Full textAbstract:
碩士國立中興大學
光電工程研究所
105
In this thesis, three series of intrinsic hydrogenated nanocrystalline silicon (nc-Si:H) films were fabricated by a pulse-wave modulated plasma-enhanced chemical vapor deposition (PECVD) system with different hydrogen dilution (R = H2/SiH4), plasma power (P), and plasma turn-on time (ton). The nc-Si:H films periodically stacked with the hydrogenated amorphous silicon (a-Si:H) to form a-Si:H/nc-Si:H superlattice films by periodically switching low and high power. Hydrogen dilution, plasma power, and plasma turn-on time were R = 40, 100, 150, P = 250 W, 500 W, 750 W, and ton = 5 ms, 10 ms, 15 ms, respectively. Transmission electron microscope (TEM) was used to observe the crystalline morphology of the nc-Si:H and a-Si:H/nc-Si:H superlattice samples. Crystallization fraction of the samples were analyzed through measuring the phonon scattering spectrum by Raman spectrum. Transmittance of the samples were measured by UV-VIS-NIR to estimate the optical bandgap (Eg) of the samples. By analyzing the crystallization fraction and bandgap variation of a-Si:H, nc-Si:H and a-Si:H/nc-Si:H superlattice thin films made by different R, P and ton, the growing process and the controllability of these thin films could be further investigated. Series of ton a-Si:H/nc-Si:H superlattice thin films were used as the intrinsic layers of p-i-n thin-film solar cells, with two structures of placing intrinsic superlattice layers near p/i interface and i/n interface. Electrical properties of the solar cells were identified by current-voltage (I-V) measurements and external quantum efficiency (EQE) measurements. The element concentrations of Si and O atoms were measured by secondary-ion mass spectrometry (SIMS) measurements. The results show that the high bandgap of the a-Si:H/nc-Si:H superlattice thin films are caused by massive oxygen doping into the nc-Si:H films. The EQE response significantly decreased from long wavelength region to short wavelength region as a-Si:H/nc-Si:H superlattice layers were moved from i/n interface to p/i interface. The high oxygen concentrations in a-Si:H/nc-Si:H superlattice contribute to the n-type doping, which could change the internal electric field of i-layer. The decreasing electric field between superlattice and i/n interface causes the long wavelength loss of EQE spectrum. The effects of internal electric field and the material qualities of superlattice on the performance of the p-i-n solar cells could be identified by placing a-Si:H/nc-Si:H superlattice at different part of i-layer. Controlling the oxygen concentrations in a-Si:H/nc-Si:H superlattice is an important issue for its application in p-i-n solar cells.
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McCann, Michelle Jane. "Aspects of Silicon Solar Cells: Thin-Film Cells and LPCVD Silicon Nitride." Phd thesis, 2002. http://hdl.handle.net/1885/47800.
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This thesis discusses the growth of thin-film silicon layers suitable for solar cells using liquid phase epitaxy and the behaviour of oxide LPCVD silicon nitride stacks on silicon in a high temperature ambient.¶ The work on thin film cells is focussed on the characteristics of layers grown using liquid phase epitaxy. The morphology resulting from different seeding patterns, the transfer of dislocations to the epitaxial layer and the lifetime of layers grown using oxide compared with carbonised photoresist barrier layers are discussed. The second half of this work discusses boron doping of epitaxial layers. Simultaneous layer growth and boron doping is demonstrated, and shown to produce a 35um thick layer with a back surface field approximately 3.5um thick.¶ ...
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Tsai, Yi-Heng, and 蔡宜恒. "Effects of Silicon Oxide Barrier Layers on Silicon Nanocrystal Thin Films." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/07229706024000460088.
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碩士國立交通大學
光電工程學系
99
In order to achieve low cost and high efficiency solar cells, all silicon tandem solar cells made of Si nanocrystal (Si NC) thin films with different bandgaps (such as Si/SiO2 Si NC thin films) stacking on crystalline Si solar cells are proposed. The solar cells can greatly reduce thermalization loss. However, Si/SiO2 Si NC thin films exhibit low conductivity because of poor conductivity of SiO2 barrier layers. In this thesis, we created additional transportation paths by increasing the defects of barrier layers. We studied effects of the defects on the crystallization and dimension of Si NC thin films by Raman spectra and XRD. In addition, we analyzed the influences of the defects on optical properties of Si NC thin films by PL spectra. Finally, we discussed a possible carrier transportation mechanism from electrical results.
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Chang-Tai, Sung, and 宋長泰. "Study of Silicon Carbide Thin Films from Polycarbosilane Acting as Buffer Layers for Diamond Film Growth." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/02420885976030101675.
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碩士國立臺灣科技大學
材料科技研究所
92
Polycarbosilane(PCS) was dissolved in toluene at various concentration levels and the resulting solutions were spun-coated onto <100>silicon wafers. The films were heat-treated under vacuum at temperatures in the range between 900℃ and 1150℃,and held for different times to from silicon carbide (SiC). The resulting SiC films were characterized using Fourier transform infrared spectrophotometer(FTIR), X-ray diffractometry (XRD), and scanning electron microscopy (SEM). The SiC films were used as buffer layers for diamond film growth. The diamond films were grown by hot filament chemical vapor deposition (HFCVD). In this study the effects of the growth pressure and subtract temperature on the morphology of diamond films were discussed. The structure of the diamond film was characterized by SEM , and XRD. The nucleation density of diamond on silicon was very low(6.2×106/cm2), but the nucleation density of diamond on SiC buffer layer was enhanced to 1.2×1011/cm2.The effect of enhancement of diamond nucleation may provide a solution for selective growth of diamond film.
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Ho, Shih, and 何軾. "Dual Scattering Layers of silica/ZnO as Light Trapping Structure for Silicon Thin Film Solar Cell." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/02597434388618884111.
Full textAbstract:
碩士國立臺灣科技大學
化學工程系
101
Silica/ZnO dual scattering layers coated on glass substrates were applied for fabrication of silicon thin film tandem solar cell. First of all, sol-gel method was used to make mono-dispersed silica particle layer as the silica light scattering layer. Preparation conditions was the concentration of ammonium hydroxide, the proportion of ethanol and the quantity of dispersing agent were systematically varied so as to investigate the morphological and optical properties of the silica scattering layer. Through spin-on a gel with silica particles 400 nm in size dispersed in 15 wt% of PVP-K30 dispersant using two step spin at 3000 rpm/4000 rpm, an effective silica scattering layer was established. Then, ZnO layer with the characteristic hexagonal (110) pyramidal surface structure was deposited on the scattering layer. Finally, TCO layer such as Ga-doped ZnO or Al-doped ZnO was grown on the ZnO layer to constitute a complete TCO glass. For device, we fabricate amorphous silicon p-i-n thin film solar cell by RF-PECVD system. The short-circuit current, open-circuit voltage and fill factor of device were 14.9 mA/cm2, 784 mV and 34.2 %, respectively. The optoelectronic conversion efficiency of 4.0 % was achieved.
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Wu, Shin-Yi, and 吳信誼. "Capacitance Force Microscopy Applied to Studies of Au thin-film and Silicon Oxide Layers." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/84253658094346607110.
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碩士國立東華大學
應用物理研究所
93
Abstract Using capacitance force microscopy (CFM) and capacitance force spectroscopy (CFS), which are two functions of atomic force microscopy (AFM), a SiO2 layer, a SiOx bump, and an Au thin-film were investigated with their surface capacitance distributions and capacitance force spectra on surface. The SiO2 layer is a native oxide layer on a Si(111) surface. The SiOx bump is an artificial oxide layer from field-induced local anodic oxidation. The Au thin-film was deposited on the Si(111) surface by an alternating-current ion sputter. The native SiO2 layer is 2 nm thick, the SiOx bump is ~2-3 nm high, and the Au thin-film is ~30 nm thick, respectively. According to CFM images, the Au thin-film has a surface capacitance (CXY), and the magnitude of the Au surface capacitance is larger than those of the SiO2 layer and SiOx bump. The Au thin-film is a good conductor, but the SiO2 layer and SiOx bump are varying insulators. The SiO2 surface capacitance is larger than the SiOx‘s, indicating that the conductor surface capacitance is larger than the semiconductor surface capacitance, and the semiconductor surface capacitance is larger than the insulator surface capacitance. From the analysis of the CFS spectra of the Au thin-film, the SiO2 layer, and the SiOx bump, the surface capacitances (CXY) and vacuum capacitance (CZ) can be found between 10-12 and 10-13 F. The effective capacitances (C) of the three samples are distinct, and Cau>Csiox>Csio2 .
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Su, Ya-hui, and 蘇雅惠. "An Angstrom-Scale Surface Smooth Technology for Transferred Single-Crystal Silicon Thin Film Layers." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/91646643847953386170.
Full textAbstract:
碩士國立中央大學
機械工程研究所
95
The technique of single-crystal Si layer transfer based on using Hydrogen ion implantation has been widely applied in the fabrication of SOI materials possessing nano-scale device layer with single-crystal quality. However, after Si layer transfer process, a lattice-defect region was formed near the surface of transferred Si layer. Therefore, this unwanted region usually needs an extra chemical mechanical polishing (CMP) process to remove it. The main purpose of this study is to avoid the above polishing process as well as simplify the manufacturing processes. In this study, the removal of lattice-defect region generated after layer transfer by Smart-cut® method used etching approach with specific etchants to etch out it at specific temperature. This etching process could also result in surface smooth of the Si transferred layer. Besides, depositing a polysilicon layer as a sacrificial layer has successfully improved the occurrence of channel effect during ion implantation process and then reduced the difference of ion penetration depth to initially modify the surface roughness of the as-split SOI thin film. The surface roughness could be further decreased after using etching approach to remove the lattice-defect region. The above two steps can make the final surface of the transferred single-crystal Si layer smooth and uniform.
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Lu, Yi-Hsien, and 呂宜憲. "Comparison of Low Temperature Thin Film Transistors with Different High-k Dielectric Layers and Conventional TEOS Silicon Dioxide Layer." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/60544032403277314846.
Full textAbstract:
碩士國立交通大學
電子物理系所
95
Abstract (English) In thesis, high-performance p-channel poly-Si thin-film transisitors (TFTs) are demonstrated using the different high-k dielectric with hafnium dioxide (HfO2), hafnium silicate (HfSiOX) layer are demonstrated by metal-organic chemical vapor deposition system with low-temperature processing. We compare with tetra-ethyl-oxy-silicate silicon dioxide (TEOS-SiO2) layer with the same physics thickness for our main shaft. Furthermore, the effect and reliability are also studied. It is found both the electric characteristic of high-k dielectric TFTs that improve obviously: including the lower threshold voltage, the better subthreshold swing, the higher on current. The main reason is imputed to the high capacitance density of high-k dielectric layers such that the grain boundary traps of poly-Si could be full faster and decrease the transition time exist in the poly-Si TFTs. However, the field effective mobility of HfO2 dielectric TFTs is lower due to the roughness interface between HfO2 layer and poly-Si channel and larger leakage current in the off state due to the high field near drain. Devices characteristics of different dielectric layers degrade with stress time and stress conditions. We found the HfSiO dielectrics TFTs have the better reliability due to it has the better interface ,higher crystalline temperature and lower density of states.
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Chen, Yu-An, and 陳璵安. "Development of Highly Conductive Hydrogenated Microcrystalline Silicon Oxide Doped Layers for Thin-Film Solar Cell Applications." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/95443703504810324156.
Full textAbstract:
碩士國立交通大學
光電工程學系
101
In this study, plasma-enhanced chemical vapor deposition (PECVD) was used to deposit hydrogenated microcrystalline silicon oxide (μc-SiOx:H) for thin-film solar cell applications. In hydrogenated amorphous silicon (a-Si:H) single-junction thin film solar cells, the thickness of the absorber layer should be thin to reduce Staebler-Wronski effect. The light trapping is necessary to achieve longer light paths to reduce the limit of the light absorption due to thinner absorber. The μc-SiOx:H with wider bandgap, lower coefficient and higher conductivity was a suitable doped layer. However, the incorporation of oxygen decreased the crystallinity as well as the conductivity. In this study, by optimizing the deposition conditions, the μc-SiOx:H film with the higher bandgap, higher conductivity and lower refractive index than that of a-Si:H was obtained. The characteristics of μc-SiOx:H n-layer was found to be similar to transparent conductive oxide (TCO). Thus, we replaced the a-Si:H(n)/TCO back reflector by a-Si:H(n)/μc-SiOx:H(n)/TCO in a-Si:H single-junction solar cell. The highest efficiency of the a-Si:H single-junction solar cell was 9.63 % with Voc = 890.1 mV, Jsc = 14.73 mA/cm2 and F.F. = 73.51%. Besides, µc-SiOx:H(n)/µc-SiOy:H(n)/Ag structure was used to replace a-Si:H(n)/TCO/Ag as back reflector (BR) structure and the best conversion efficiency in this study was 9.60%.
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Cho, Li-ping, and 卓立苹. "Study on Light Shielding layer of Polycrystalline Silicon Thin-Film Transistor." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/02706864367137225986.
Full textAbstract:
碩士國立交通大學
理學院碩士在職專班應用科技學程
95
Abstract Since poly-Si TFTs are widely used in active-matrix liquid crystal display (AMLCD), they usually will be exposed to the scattered light from the backlight system. In this paper, The Poly-Si TFTs with light shielding in order to suppress photo-leakage currents, which is essential to realize a high contrast ratio in display images. The C-V (capacitance-voltage) analysis observer poly-Si TFTs characteristics, which adjust measure frequency and compare structure differences. Today studies, the photon energy will be absorbed by the silicon film to excite the generation of electron-hole pairs. Under certain electric field such as the built-in electric field in the depletion regions, the electron and the hole will move toward the opposite direction and from the current. Compared to the generation current from the depletion in the dark environment, the light caused current is much larger and cause pronounced leakage current problem. We use the well-absorbing a-Si silicon film (amorphous silicon film) to be the light-shielding layer. The variation in the C-V result allows us to identify the degradation mechanism in the dark and illumination circumstance.
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Tseng, Yi-Wen, and 曾奕文. "Study of Amorphous and Microcrystalline Silicon Oxide as Absorber and Doped Layers for Thin-film Solar Cell Applications." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/93305949398124657133.
Full textAbstract:
碩士國立交通大學
光電工程學系
100
In this study, plasma-enhanced chemical vapor deposition (PECVD) was used to deposit hydrogenated amorphous (a-SiOx:H) and microcrystalline (μc-SiOx:H) silicon oxide for thin-film solar cell applications. In order to effectively enhance the broaden spectral response, tandem or multi-junction structure was employed. The wider bandgap amorphous silicon oxide (a-SiOx:H) was a suitable absorber for the top cell. In this thesis, we first studied the characteristics of a-SiOx:H thin-films and the performance of a-SiOx:H single-junction solar cells. The optimized efficiency was 4.43%. Then we used a-SiOx:H absorber as the top cell in an a-SiOx:H/a-SiGe:H tandem solar cell. The Jsc increased and F.F. decreased with increasing in the thickness of top cell. The highest efficiency of a-SiOx:H/a-SiGe:H tandem solar cell was 7.38%. Moreover, the μc-SiOx:H with wider bandgap, lower absorption coefficient and higher conductivity was a suitable doped layers. However, the incorporation of oxygen decreased the crystalline fraction as well as the conductivity. In this study, by optimizing the deposition conditions, the μc-SiOx:H film with the higher bandgap, higher conductivity and lower refractive index than that of a-Si:H was obtained. The characteristics of μc-SiOx:H n-layer was found to be similar to transparent conductive oxide (TCO). Thus, we replaced the a-Si:H(n)/TCO back reflector by μc-SiOx:H(n) in a-Si:H single-junction solar cell. The highest efficiency of the a-Si:H single-junction solar cell was 9.92% with Voc = 900 mV, Jsc = 15.17 mA/cm2 and F.F. = 72.7%.
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Lee, Yen-Po, and 李彥伯. "Study of the Properties Based on Silicon Thin Film Solar Cell Thin Silver Reflective Layer." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/yx5763.
Full textAbstract:
碩士國立臺北科技大學
光電與能源產業研發碩士專班
99
The main purpose of this study was to investigate the amorphous silicon p-i-n solar cell production in the silver reflective layer of optical and electrical properties of electrodes.. First is to utilize the power coupled plasma chemical vapor deposition system (plasma-enhanced chemical vapor deposition, PECVD) amorphous silicon hydrogen to be prepared film (a-Si: H) materials; first grown on Si substrate layer a-Si: H buffer layer , and then deposited p-type a-Si: H film, then use the hydrogen plasma treatment a-Si: H buffer layer, and then deposited a-Si: H films by hydrogen dilution of source gases SiH4 way deposition n-type a -SiC: H films, and then in n-type a-SiC: H films by RF magnetron sputtering system (Radio-Frequency magnetron sputtering system) sputtered AZO, with yellow for the silver electrode technology, complete with silver reflective layer of pin solar cells. T Finally, simulated sunlight light AM 1.5 illumination condition with a solar intensity of 100 mW/cm2 without silver electrodes get the short-circuit current density Jsc = 2.614 mA/cm2, the open-circuit voltage Voc = 630mV, the fill factor FF = 0.255, and the power conversion efficiencies η = 4.2%.；with silver electrodes get the short-circuit current density Jsc = 3.86 mA/cm2, the open-circuit voltage Voc = 630mV, the fill factor FF = 0.255, and the power conversion efficiencies η = 6.21%. Study Showing with silver electrode of solar cells ，the short-circuit current the increase of 12.7%, 12.9% energy conversion efficiency
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Chen, Pei-Ling, and 陳珮伶. "Development of Hydrogenated Silicon Sub-oxide Doped Layers and Light Trapping Structures for Enhancing Light Management in Silicon-based Thin-film Solar Cells." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/fyp6p6.
Full textAbstract:
博士國立交通大學
光電工程研究所
106
We developed and characterized the hydrogenated silicon sub-oxide doped layers and light trapping structures for enhancing light managements in silicon-based thin-film solar cell. This thesis covers five main research topics: (i) development of p-type μc-SiOx:H with wide bandgap and high conductivity by optimizing deposition conditions, (ii) development of p-type SiOx:H alloy prepared in transition region with high conductivity as window layer in a-Si:H/a-Si1-yGey:H tandem cells by adjusting H2-to-SiH4 flow ratio (RH2), (iii) development of p-type and n-type μc-SiOx:H with wide bandgap, and high conductivity as p-layer of the bottom cell and back-reflecting layer (BRL) in a-Si:H/μc-Si:H tandem cells, (iv) applications of optimized p-type and n-type μc-SiOx:H as dual-functional intermediate reflection layer and tunneling recombination junction (IRL/TRJ) in a-Si:H/μc-Si1-zGez:H tandem cells, and (v) development of assembled Ag nanoparticles (Ag NPs) by chemical method and periodic SiO2 light trapping structures by nanoimprint technology in a-Si:H/a-Si1-yGey:H tandem cells. The p-type c-SiOx:H thin-films were deposited by radio-frequency plasma-enhanced chemical vapor deposition (RF-PECVD). By increasing RH2 and deposition pressure, the film exhibited the increased conductivity of 0.23 S/cm and the enhanced crystalline volume fraction (XC) of 43.7%. However, under higher pressure process conditions, the degraded the conductivity of 1.37×10-3 S/cm and XC of 32.7% was observed, resulting from the insufficient hydrogen etching during film growth. The p-type SiOx:H films were prepared in the transition region as a window layer in a-Si:H/a-Si1-yGey:H tandem cells. By increasing the RH2 from 10 to 167, the SiOx:H(p) remained amorphous and exhibited an increased hydrogen content. Compared to the a-SiOx:H(p) prepared at low-RH2, the SiOx:H(p) deposited at the RH2 of 167 exhibited a wide bandgap of 2.04 eV and a higher conductivity of 1.15×10-5 S/cm. With the employment of SiOx:H(p) prepared by increasing RH2 from 10 to 167 in a-Si:H cells, the FF was improved from 65 to 70% and the efficiency increased from 7.4 to 8.7%. However, the cell employed SiOx:H(p) with RH2 over 175 degraded the p/i interface and the cell performance. The a-Si:H/a-Si1-yGey:H tandem cells employing SiOx:H(p) deposited with RH2 of 167 showed an efficiency of 10.3%, with VOC of 1.60 V, JSC of 9.3 mA/cm2 and FF of 68.9%. The p-type and n-type μc-SiOx:H were prepared as doped layers of bottom cell in a-Si:H/μc-Si:H tandem cells. Regarding the doped μc-SiOx:H films, the wide optical bandgap (E04) of 2.33 eV while maintaining a high conductivity of 0.2 S/cm could be obtained with [O] of 20 at.%. Compared to the μc-Si:H(p) as window layer in μc-Si:H cells, the application of μc-SiOx:H(p) increased the VOC and led to a significant enhancement in the short-wavelength spectral response. Meanwhile, the employment of μc-SiOx:H(n) instead of conventional ITO as BRL enhanced the spectral response in the long-wavelength region. Compared to the reference cell, the optimized a-Si:H/μc-Si:H tandem cell by with p-type and n-type μc-SiOx:H exhibited an efficiency of 10.51%, which was a relative enhancement of 16%. The p-type and n-type c-SiOx:H films were prepared as functional layers in IRL/TRJ structures for a-Si:H/c-Si1-zGez:H tandem cell applications. Compared to the reference cell without the IRL/TRJ structure, the cell with µc-SiOx:H(n)/µc-Si:H(n)/µc-Si:H(p) structure as IRL/TRJ showed a significant increase in FF from 57.3 to 69.3% without the S-shaped J-V curve. Furthermore, replacing µc-Si:H(p) with µc-SiOx:H(p) increased the VOC from 1.32 to 1.35 V due to the higher E04 than µc-Si:H(p). Using the µc-SiOx:H(n)/µc-SiOx:H(p) as IRL/TRL structure in tandem cells exhibited the improved FF of 72.1% and the efficiency of 9.6%. After optimizing the CO2-to-SiH4 flow ratio (RCO2) and the thickness of µc-SiOx:H(n) IRL layer, the high efficiency of 11.6% was obtained by employing 40-nm-thick µc-SiOx:H(n) prepared at RCO2 of 1. The chemically assembled Ag NPs and the periodic SiO2 structure were developed to enhance the light management in a-Si:H/a-Si1-yGey:H tandem cells. With increasing Na3C6H5O7 concentration, the segregated Ag NPs employed in tandem cells increased spectral response in long-wavelength. In addition, as the Ag particle size increased, the increased spectral response in long-wavelength was due to the increased diffuse reflectance. However, too larger particle size than 150 nm decreased spectral response. The optimized a-Si:H/a-Si1-yGey:H tandem cell by employing Ag NPs of 150 nm prepared at Na3C6H5O7 concentration of 20 mM showed a high efficiency of 9.54%. Regarding the SiO2 structure on SnO2:F side in solar cells, with increasing the pillar height, the obviously increased spectral response was due to the increased roughness on surface. However, as the pillar height was over 200 nm, the decreased spectral response was ascribed to the remained interstitial SiO2. The optimal a-Si:H/a-Si1-yGey:H tandem cells by employing SiO2 with pillar height of 150 nm obtained an efficiency of 8.81%.