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Florentín, Matthieu. "Irradiation impact on optimized 4H-SiC MOSFETs". Doctoral thesis, Universitat Politècnica de Catalunya, 2016. http://hdl.handle.net/10803/395187.
Pełny tekst źródłaLas tecnologías de dispositivos de potencia en silicio (Si) han alcanzado una gran madurez. Sin embargo, las limitaciones del Si debidas a sus restricciones mecánicas, térmicas y eléctricas hacen necesario otros materiales semiconductores que puedan competir con el Si y superar sus limitaciones. Este es el caso del Carburo de Silicio (SiC) y del Nitruro de Galio (GaN) que ya comienzan a ser serios competidores del Si debido a sus mejores propiedades físicas. En lo que respecta al SiC, el politipo 4H es el candidato más adecuado para la integración de MOSFETs de potencia debido, entre otros, a los valores del bandgap, campo eléctrico crítico, movilidad volumíca de los electrones y tensión umbral alcanzable. A pesar de estas ventajas teóricas del material, es necesario optimizar cada uno de los procesos tecnológicos involucrados en la fabricación de un MOSFET en SiC para que realmente pueda competir con su contrapartida en Si. Este es el caso del proceso de oxidación para la formación del dieléctrico de puerta. Concretamente, una buena estabilidad de la tensión umbral del componente requiere disminuir la densidad de cargas en la interfase óxido/semiconductor, y mejoras adicionales en la calidad de esta interfase son también necesarias para obtener altos valores de la movilidad de los portadores en el canal de inversión. La solución de los problemas tecnológicos anteriormente enunciados abrirá nuevas perspectivas a las aplicaciones de alta potencia. Este trabajo es una continuación directa del de Aurore Constant. Se centra en dispositivos basados en 4H-SiC, y más específicamente en los procesos de oxidación de puerta, y de sus comportamientos eléctricos en diferente ambientes de trabajo hostiles. Hasta la fecha, la mayor parte de la investigación se ha centrado en la mejora de la calidad de la interfase dióxido de silicio/carburo de silicio (SiO2/SiC). La solución de estos problemas debería permitir el diseño de MOSFETs muy rápidos y con pérdidas de conmutación muy bajas. El objetivo del trabajo previo de Aurore Constant fue encontrar un nuevo procedimiento de limpieza de la superficie antes de realizar la oxidación, y en definir un nuevo proceso de oxidación para la formación del dieléctrico de puerta. Los resultados obtenidos mostraron claras mejoras del comportamiento eléctrico de los componentes. Sin embargo, estamos convencidos que la mejora podría ser aún mayor optimizando la etapa del recocido post-oxidación, utilizando un proceso adicional de dopaje superficial, o realizando un adecuado proceso de irradiación. Todos los esfuerzos de este trabajo se han dirigido al desarrollo de MOSFETs en SiC fiables, con mejores características eléctricas, y capaces de trabajar en ambientes de alta temperatura y de irradiación protónica o electrónica. En resumen, las principales líneas de esta Tesis son las siguientes: 1. Estado del arte de los diferentes dominios de trabajo del SiC. 2. Procesos y técnicas de caracterización eléctrica. 3. Impacto de la irradiación de protones en MOSFETs fabricados en 4H-SiC, y descripción teórica de los mecanismos de creación de carga en la interfase SiO2/SiC. 4. Impacto de la irradiación electrónica en MOSFETs fabricados en 4H-SiC. 5. Optimización de los procesos de oxidación y de implantación. 6. Límite de robustez de los procesos tecnológicos optimizados en ámbitos irradiados.
Robert, Teddy. "Spectroscopie des fautes d'empilement dans 4H-SiC". Montpellier 2, 2009. http://www.theses.fr/2009MON20166.
Pełny tekst źródłaLi, Mingyu Williams John R. "Ohmic contacts to implanted (0001) 4H-SiC". Auburn, Ala., 2009. http://hdl.handle.net/10415/1960.
Pełny tekst źródłaHaasmann, Daniel Erwin. "Active Defects in 4H–SiC MOS Devices". Thesis, Griffith University, 2015. http://hdl.handle.net/10072/367037.
Pełny tekst źródłaThesis (PhD Doctorate)
Doctor of Philosophy (PhD)
Griffith School of Engineering
Science, Environment, Engineering and Technology
Full Text
Horita, Masahiro. "Isopolytypic Growth of Nonpolar 4H-AlN on 4H-SiC and Its Device Applications". 京都大学 (Kyoto University), 2009. http://hdl.handle.net/2433/81830.
Pełny tekst źródłaSejil, Selsabil. "Optimisation de l'épitaxie VLS du semiconducteur 4H-SiC : Réalisation de dopages localisés dans 4H-SiC par épitaxie VLS et application aux composants de puissance SiC". Thesis, Lyon, 2017. http://www.theses.fr/2017LYSE1170/document.
Pełny tekst źródłaThe objective of the VELSIC project has been to demonstrate the feasibility of 1 µm deep p+/n- junctions with high electrical quality in 4H-SiC semiconductor, in which the p++ zone is implemented by an original low-temperature localized epitaxy process ( 1100 - 1200 °C ), performed in the VLS (Vapor - Liquid - Solid) configuration. This innovative epitaxy doping technique uses the monocrystalline SiC substrate as a crystal growth seed. On the substrate (0001-Si) surface, buried patterns of Al - Si stack are fused to form liquid islands which are fed with carbon by C3H8 in the gas phase. This method is investigated as a possible higher performance alternative to the ion implantation process, currently used by all manufacturers of SiC devices, but which still experiences problematic limitations that are yet unresolved to date. Although the main focus of the study has been set on the optimization of localized VLS epitaxy, our works have explored and optimized all the facets of the complete process of test diodes, from the etching of patterns in the SiC substrate up to the electrical I - V characterization of true pn diodes with ohmic contacts on both sides.Our results have confirmed the need to limit the growth rate down to 1 µm/h to maintain good crystallinity of the epitaxial material. It has also highlighted the direct action of the radiofrequency electromagnetic field on the liquid phase, leading to a very strong influence of the diameter of the etched patterns on the thickness of the deposited SiC. A nearly complete filling of the 1 µm deep trenches with very high p++ doping has been demonstrated. Using optimized VLS growth parameters, p+/n- diode demonstrators have been processed and tested. On the best samples, without passivation or peripheral protection, high direct-current threshold voltages, between 2.5 and 3 V, were measured for the first time without any high-temperature annealing after epitaxy. These threshold voltage values correspond to the expected values for a true p-n junction on 4H-SiC. Current densities of several kA/cm2 have also been injected at voltages around 5 - 6 V. Under reverse bias conditions, no breakdown is observed up to 400 V and low leakage current densities at low electric field, in the range 10 - 100 nA/cm2, have been measured. All these advances align with or exceed state-of-the-art results for such simple SiC devices, obtained using any doping technique
Usman, Muhammad. "Impact of Ionizing Radiation on 4H-SiC Devices". Doctoral thesis, KTH, Integrerade komponenter och kretsar, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-60763.
Pełny tekst źródłaQC 20120117
Zeng, Yutong. "Tailored Al2O3/4H-SiC interface using ion implantation". Thesis, KTH, Skolan för informations- och kommunikationsteknik (ICT), 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-90233.
Pełny tekst źródłaKaralas, Charilaos-Kimonas. "Process optimization for the 4H-SiC/SiO2 interface". Thesis, KTH, Skolan för informations- och kommunikationsteknik (ICT), 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-174842.
Pełny tekst źródłaSuvanam, Sethu Saveda. "Radiation Hardness of 4H-SiC Devices and Circuits". Doctoral thesis, KTH, Integrerade komponenter och kretsar, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-199907.
Pełny tekst źródłaQC 20170119
Padavala, Balabalaji. "Epitaxy of boron phosphide on AIN, 4H-SiC, 3C-SiC and ZrB₂ substrates". Diss., Kansas State University, 2016. http://hdl.handle.net/2097/32808.
Pełny tekst źródłaDepartment of Chemical Engineering
James H. Edgar
The semiconductor boron phosphide (BP) has many outstanding features making it attractive for developing various electronic devices, including neutron detectors. In order to improve the efficiency of these devices, BP must have high crystal quality along with the best possible electrical properties. This research is focused on growing high quality crystalline BP films on a variety of superior substrates like AIN, 4H-SiC, 3C-SiC and ZrB₂ by chemical vapor deposition. In particular, the influence of various parameters such as temperature, reactant flow rates, and substrate type and its crystalline orientation on the properties of BP films were studied in detail. Twin-free BP films were produced by depositing on off-axis 4H-SiC(0001) substrate tilted 4° toward [1-100] and crystal symmetry matched zincblende 3C-SiC. BP crystalline quality improved at higher deposition temperature (1200°C) when deposited on AlN, 4H-SiC, whereas increased strain in 3C-SiC and increased boron segregation in ZrB₂ at higher temperatures limited the best deposition temperature to below 1200°C. In addition, higher flow ratios of PH₃ to B₂H₆ resulted in smoother films and improved quality of BP on all substrates. The FWHM of the Raman peak (6.1 cm⁻¹), XRD BP(111) peak FWHM (0.18°) and peak ratios of BP(111)/(200) = 5157 and BP(111)/(220) = 7226 measured on AlN/sapphire were the best values reported in the literature for BP epitaxial films. The undoped films on AlN/sapphire were n-type with a highest electron mobility of 37.8 cm²/V·s and a lowest carrier concentration of 3.15x1018 cm⁻ᶟ. Raman imaging had lower values of FWHM (4.8 cm⁻¹) and a standard deviation (0.56 cm⁻¹) for BP films on AlN/sapphire compared to 4H-SiC, 3C-SiC substrates. X-ray diffraction and Raman spectroscopy revealed residual tensile strain in BP on 4H-SiC, 3C-SiC, ZrB₂/4H-SiC, bulk AlN substrates while compressive strain was evident on AlN/sapphire and bulk ZrB₂ substrates. Among the substrates studied, AlN/sapphire proved to be the best choice for BP epitaxy, even though it did not eliminate rotational twinning in BP. The substrates investigated in this work were found to be viable for BP epitaxy and show promising potential for further enhancement of BP properties.
Moghadam, Hamid Amini. "Quantified Characterization of Active Defects in 4H–SiC MOS Devices". Thesis, Griffith University, 2016. http://hdl.handle.net/10072/366432.
Pełny tekst źródłaThesis (PhD Doctorate)
Doctor of Philosophy (PhD)
Griffith School of Engineering
Science, Environment, Engineering and Technology
Full Text
Lin, Huang-De Hennessy. "Low-temperature halo-carbon homoepitaxial growth of 4H-SiC". Diss., Mississippi State : Mississippi State University, 2008. http://library.msstate.edu/etd/show.asp?etd=etd-10142008-150935.
Pełny tekst źródłaEktarawong, Annop. "Growth and characterization of graphene on 4H-SiC(0001)". Thesis, Linköpings universitet, Halvledarmaterial, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-82014.
Pełny tekst źródłaKwasnicki, Pawel. "Evaluation of doping in 4H-SiC by optical spectroscopies". Thesis, Montpellier 2, 2014. http://www.theses.fr/2014MON20145/document.
Pełny tekst źródłaThe main topic of this thesis is the optical characterization of 4H-SiC samples. The samples were divided in 2 groups: type-n doped with nitrogen and type-p doped with aluminum. Samples were grown by CVD method performed in a horizontal, hot wall, resistively heated, using hydrogen as a carrier gas and silane/propane as Si/C precursors respectively. To achieve different doping N2 for n-type and TMA for p-type were used. The samples were studied by three different spectroscopies techniques: low temperature photoluminescence, micro-Raman and secondary ion mass spectroscopies. For p-type samples Hall effect measurements were used to determine carrier concentration. With the help of this techniques it was possible to determine doping level in a very large range for both types. Both LTPL and Raman spectroscopy can give information about the polytype, crystal quality and carrier concentration but only LTPL provides information about compensation and is indispensable to define the polarity. For low doped samples since the LOPC & FTA modes of Raman spectra do not exhibit any significant changes the best ways seems to be LTPL measurements. For the highest doped samples notice the advantage of Raman which allows to determine the carrier concentration up to 10^20cm-3. Finally due to electrical measurements and fano-paremeters obtained by micro-Raman spectra we made calibration curve for p –type 4H-SiC
Domeij, Martin. "Dynamic avalanche in Si and 4H-SiC power diodes /". Stockholm, 1999. http://www.lib.kth.se/abs99/dome0604.pdf.
Pełny tekst źródłaSolomon, Ruth Reena. "Fabrication and characterization of Cu/4H-SiC Schottky diodes". Connect to this title online, 2007. http://etd.lib.clemson.edu/documents/1193079981/.
Pełny tekst źródłaBenjamin, Helen N. "Non-contact characterization of dielectric conduction on 4H-SiC". [Tampa, Fla] : University of South Florida, 2009. http://purl.fcla.edu/usf/dc/et/SFE0002984.
Pełny tekst źródłaJiang, Chennan. "Damage accumulation and recovery in Xe implanted 4H-SiC". Thesis, Poitiers, 2018. http://www.theses.fr/2018POIT2251/document.
Pełny tekst źródłaSilicon carbide is a material that can be considered as a wide band gap semiconductor or as a ceramic according to its applications in microelectronics and in nuclear energy system (fission and fusion). In both fields of application defects or damage induced by ion implantation/ irradiation (doping, material structure) should be controlled. This work is a study of defects induced by noble gas implantation according to the implantation conditions (fluence and temperature). The elastic strain buildup, particularly in the case of xenon implantation, has been studied at elevated temperatures for which the dynamic recombination prevents the amorphization transition. A phenomenological model based on cascade recovery has been proposed to understand the strain evolution with increasing dose and for different noble gases. In addition, with the help of transmission electron microscopy the evolution of defects under subsequent annealing was studied. The formation of nanocavities was observed under severe implantation/annealing conditions. These cavities are of different nature (full of gas or empty) according to the xenon and damage distribution. This study is also linked to swelling properties under irradiation that should be projected in the SiC application fields
Freda, Albanese Loredana. "Characterization, modeling and simulation of 4H-SiC power diodes". Doctoral thesis, Universita degli studi di Salerno, 2011. http://hdl.handle.net/10556/217.
Pełny tekst źródłaExploring the attractive electrical properties of the Silicon Carbide (SiC) for power devices, the characterization and the analysis of 4H-SiC pin diodes is the main topic of this Ph.D. document. In particular, the thesis concerns the development of an auto consistent, analytical, physics based model, created for accurately replicating the power diodes behavior, including both on-state and transient conditions. At the present, the fabrication of SiC devices with the given performances is not completely obvious because of the lack of knowledge still existing in the physical properties of the material, especially of those related to carrier transport and of their dependences on process parameters. Among these, one can cite the degree of doping activation, the carrier lifetime into epitaxial layers that will be employed and the sensitivity of some physical parameters to temperature changes. Therefore, a set of investigative tools, designed especially for SiC devices, cannot be regarded as secondary objective. It will be useful both for process monitoring, becoming essential to the tuning of technological processes used for the implementation of the final devices, and for a proper diagnostics of the realized devices. Following this need, in our research activity firstly a predictive, static analytical model, including temperature dependence, is developed. It is able to explain the carrier transport in diffused regions as function of the injection level and turns also useful for better understanding the influence of physical parameters, which depend in a significant way from the processed material, on device performances. The model solves the continuity equation in double carrier conditions, taking into account the effects due to varying doping profile of the junction, the spatial dependence of physical parameters on both doping and injection level and the modification of the electric field of the region with the injection regime. The model includes also the device characterization at high temperatures to analyze the influence of thermal issues on the overall behavior up to temperature of 250°C. The accuracy of the static model has been extensively demonstrated by numerous comparisons with numerical results obtained by the SILVACO commercial simulator. Secondly, with the aim to properly account for the dynamic electrical behavior of a diode with generic structure, the static model has been incorporated in a more general, self-consistent model, allowing the analysis of the device behavior when it is switched from an arbitrary forward-bias condition. In particular, the attention is focused on an abrupt variation of diode voltage due to an instantaneous interruption of the conduction current: although this situation is notably interesting for the study of the switching behavior of diodes, the voltage transitory is also traditionally used in different techniques of investigation to extract more information about the mean carrier lifetime. This occurs, for example, in the conventional Open Circuit Voltage Decay (OCVD) technique, where the voltage decay due to the current interruption is useful for an indirect measure of minority carrier lifetime in the epitaxial layer. Because of its heavy dependence on processes, the carrier lifetime is an important parameter to be monitored, especially in the case of bipolar devices, and it cannot be neglected. Due to the existent uncertainty about this parameter in SiC epi-layers, the OCVD method reveals itself a practical way to overcoming this limit. In detail, by using our self-consistent model, that exploits an improved method of the traditional OCVD technique, it is possible to characterize the carrier lifetime into 4H-SiC epitaxial layer of a generic diode under test, obtaining the spatial distributions of the minority carrier concentration and carrier lifetime at any injection regime. The overall model performances are compared to both device simulations and experimental results performed on Si and 4H-SiC rectifier structures with various physical and electrical characteristics. From the comparisons, the model results to have good predictive capabilities for describing the spatial–temporal variation of carriers and currents along the whole epi-layer, proving contextually the validity of the used approximations and allowing also to resolve some ambiguities reported in the literature, such as the stated inapplicability of the OCVD method on thick epitaxial layers, the reasons of the observed non linear decay of the voltage with time, and the effects of junction properties on voltage transient. Finally, with the imposition of right boundary conditions, it is possible to use the versatility of the developed model for extending the analysis and obtaining a physical insight of any arbitrary switching condition of 4H-SiC power diodes. [edited by author]
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Song, Xi. "Activation des dopants implantés dans le carbure de silicium (3C-SiC et 4H-SiC)". Thesis, Tours, 2012. http://www.theses.fr/2012TOUR4019/document.
Pełny tekst źródłaThis work was dedicated to the activation of implanted dopants in 3C-SiC and 4H-SiC. The goal is to propose optimized process conditions for n-type implantation in 3C-SiC and for p-type in 4H-SiC.We have first studied the n-type implantation in 3C-SiC. To do so, N, P implantations, N&P co-implantation and the associated annealings were performed. The nitrogen implanted sample, annealed at 1400°C-30 min evidences a dopant activation rate close to 100% while maintaining a good crystal quality. Furthermore, the electrical properties of extended defects in 3C-SiC have been studied. Using the SSRM measurements, we have evidenced for the first time that these defects have a very high electrical activity and as a consequence on future devices.Then, we have realized a study on p-type doping by Al implantation in 4H-SiC with different implantation and annealing temperatures. Al implantation at 200°C followed by an annealing at 1850°C-30min lead to the best results in terms of physical and electrical properties
Shin, Yun ji. "Étude du procédé de croissance en solution à haute température pour le développement de substrats de 4H-SiC fortement dopes". Thesis, Université Grenoble Alpes (ComUE), 2016. http://www.theses.fr/2016GREAI058/document.
Pełny tekst źródłaSilicon Carbide is a wide band gap semiconductor which has recently imposed as a key material for modern power electronics. Bulk single crystals and active epilayers are industrially produced by vapor phase processes, namely seeded sublimation growth (PVT) and chemical vapor deposition (CVD) respectively. The high temperature solution growth is currently being revisited due to its potential for achieving high structural quality. This work is a contribution to the development of the top seeded solution growth (TSSG) process, with a special focus on heavily p-type doped 4H-SiC crystals. Aluminum (Al) is the most commonly used acceptor in SiC. Different elementary steps of the process are studied, and for every cases, the effect of Al is considered and discussed. After a brief history of SiC material, basic structural and physical properties of silicon carbide are introduced in chapter 1 and discussed with respect to power electronics applications. In chapter 2, the crystal growth puller is detailed and the three most important technical issues of the SiC solution growth process are discussed : i) carbon supply by dissolution at the graphite crucible/liquid interface, ii) carbon transport from the dissolution area to the growth front, and iii) crystallization on the seed substrate. These three steps are studied and improved by adding transition metals (Fe or Cr) to the solvent in order to increase the carbon solubility, by increasing the carbon transport with the optimization of the forced convection (i.e. rotation of the crystal) and by stabilizing the growth front. After optimization, a 4H-SiC crystal is demonstrated with a growth rate of over 300 µm/h and a diameter enlargement of about 41% compared to the original seed size. Chapter 3 is dedicated to the investigation of the interaction between the liquid solvent and the 4H-SiC surface under equilibrium conditions, i.e. without any growth, using a sessile drop method. Effect of time, temperature and the addition of Al to pure liquid silicon are investigated. It is shown that the liquid/solid exhibits a three stages evolution: i) dissolution, ii) step bunching and iii) faceting, the original step and terrace structure being decomposed into (0001), (10-1n) and (01-1n) facets. Increasing the temperature from 1600°C to 1800°C or adding Al drastically enhances the second stage, but reduces the third one. In chapter 4, transient phenomena during the seeding stage of the growth process on the seed crystal are investigated. With the help of numerical modeling, it is shown that strong temperature fluctuations during the contact between the seed and the liquid can give rise to transient 3C-SiC nucleation on the crystal surface, even at high temperatures. This phenomenon can be avoided by either pre-heating the seed or by adding Al. Increasing forced convection (rotation rate of the crystal) is a good way to increase the growth rate. However, above a critical rotation rate, a special surface instability develops. It is based on the interaction between the step flow at the growing surface and the local fluid flow directions close to the surface. This is investigated in Chapter 5. Finally, carrier concentrations and total dopant (nitrogen and aluminum) concentrations are investigated as a function of different process parameters in chapter 6. Al incorporation as high as 5E+20 at/cm3 has been achieved in layers grown at 1850°C. This value is very promising for the future development of p+ 4H-SiC substrates
Österman, John. "Characterization of electrical properties in 4H-SiC by imaging techniques". Doctoral thesis, KTH, Microelectronics and Information Technology, IMIT, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-64.
Pełny tekst źródła4H-SiC has physical properties supremely suited for a variety of high power, high frequency and high temperature electronic device applications. To fully take advantage of the material's potential, several problems remain to be solved. Two of the most important are (1) the characterization and understanding of crystallographic defects and their electrical impact on device performance, and (2) the introduction of acceptor dopants, their activation and control of the final distribution of charge carriers. Two main experimental methods have been employed in this thesis to analyze 4H-SiC material with respect to the issues (1) and (2): electron beam induced current (EBIC) and scanning spreading resistance microscopy (SSRM), respectively.
EBIC yields a map of electron-hole-pairs generated by the electron beam of a scanning electron microscope and collected in the depleted region around a junction. EBIC is conducted in two modes. In the first mode the EBIC contrast constitutes a map of minority carrier diffusion lengths. Results from these measurements are compared to white beam syncrotron x-ray topography and reveal a one-to-one correlation between lattice distortions and the electron diffusion length in n+p 4H-SiC diodes. In the second EBIC mode, the junction is highly reverse biased and local avalanche processes can be studied. By correlating these EBIC results with other techniques it is possible to separate defects detrimental to device performance from others more benign.
SSRM is a scanning probe microscopy technique that monitors carrier distributions in semiconductors. The method is for the first time successfully applied to 4H-SiC and compared to alternative carrier profiling techniques; spreading resistance profiling (SRP), scanning electron microscopy (SEM) and scanning capacitance microscopy (SCM). SCM successfully monitors the doping levels and junctions, but none of these techniques fulfill the requirements of detection resolution, dynamic range and reproducibility. The SSRM current shows on the other hand a nearly ideal behavior as a function of aluminum doping in epitaxially grown samples. However, the I-V dependence is highly non-linear and the extremely high currents measured indicate a broadening of the contact area and possibly an increased ionization due to sample heating. Finite element calculations are performed to further elucidate these effects.
SSRM is also applied to characterize Al implantations as a function of anneal time and temperature. The Al doping profiles are imaged on cleaved cross-sections and the measured SSRM current is integrated with respect to depth to obtain a value of the total activation. The evaluation of the annealing series shows a continuous increase of the activation even up to 1950 °C. Other demonstrated SSRM applications include local characterization of electrical field strength in passivating layers of Al2O3, and lateral diffusion and doping properties of implanted boron.
Rong, Hua. "Development of 4H-SiC power MOSFETs for high voltage applications". Thesis, University of Warwick, 2015. http://wrap.warwick.ac.uk/79426/.
Pełny tekst źródłaWolborski, Maciej. "Characterization of dielectric layers for passivation of 4H-SiC devices". Doctoral thesis, Stockholm : Laboratory of Solid State Electronics, Department of Microelectronics and Applied Physics, Royal Institute of Technology (KTH), 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4229.
Pełny tekst źródłaVirojanadara, Chariya. "Studies of surface and interface properties of 4H-SiC/SiO₂ /". Linköping : Univ, 2004. http://www.bibl.liu.se/liupubl/disp/disp2004/tek890s.pdf.
Pełny tekst źródłaMorrison, Dominique Johanne. "The fabrication and characterisation of 4H-SiC Schottky barrier diodes". Thesis, University of Newcastle Upon Tyne, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.324784.
Pełny tekst źródłaMohammadi, Zohreh. "Design, simulation, fabrication and characterisation of 4H-SiC trench MOSFETs". Thesis, University of Warwick, 2018. http://wrap.warwick.ac.uk/109953/.
Pełny tekst źródłaFisher, Craig A. "Development of 4H-SiC PiN diodes for high voltage applications". Thesis, University of Warwick, 2014. http://wrap.warwick.ac.uk/62126/.
Pełny tekst źródłaRajgopal, Srihari. "FABRICATION AND CHARACTERIZATION OF 4H-SiC JFET-BASED INTEGRATED CIRCUITS". Case Western Reserve University School of Graduate Studies / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=case154350167704502.
Pełny tekst źródłaElahipanah, Hossein. "Design Optimization and Realization of 4H-SiC Bipolar Junction Transistors". Doctoral thesis, KTH, Elektronik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-211659.
Pełny tekst źródłaQC 20170810
Tsirimpis, Athanasios [Verfasser], i Heiko [Gutachter] Weber. "Investigation of Implanted Boron in 4H-SiC and Iron in 3C-SiC and Experimental/Theoretical Analysis of the Depletion Zone in 4H-SiC MOS Capacitors / Athanasios Tsirimpis ; Gutachter: Heiko Weber". Erlangen : Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 2018. http://d-nb.info/1155590627/34.
Pełny tekst źródłaChanda, Sashi Kumar. "INVESTIGATION OF DEFECTS IN N-TYPE 4H-SIC AND SEMI-INSULATING 6H-SIC USING PHOTOLUMINESCENCE SPECTROSCOPY". MSSTATE, 2005. http://sun.library.msstate.edu/ETD-db/theses/available/etd-07072005-102232/.
Pełny tekst źródłaAlexandru, Mihaela. "4H-SiC Integrated circuits for high temperature and harsh environment applications". Doctoral thesis, Universitat Politècnica de Catalunya, 2013. http://hdl.handle.net/10803/129635.
Pełny tekst źródłaLades, Martin. "Modeling and simulation of wide bandgap semiconductor devices 4H/6H-SiC /". [S.l. : s.n.], 2000. http://deposit.ddb.de/cgi-bin/dokserv?idn=962057827.
Pełny tekst źródłaPourbagheri, Mahabadi Haniyeh. "Optical studies of surface recombination velocity in 4H-SiC epitaxial layer". Thesis, KTH, Skolan för informations- och kommunikationsteknik (ICT), 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-37225.
Pełny tekst źródłaCristiano, Marco. "Design considerations for a high temperature image sensor in 4H-SiC". Thesis, KTH, Skolan för informations- och kommunikationsteknik (ICT), 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-185268.
Pełny tekst źródłaBouhafs, Chamseddine. "Structural and Electronic Properties of Graphene on 4H- and 3C-SiC". Doctoral thesis, Linköpings universitet, Halvledarmaterial, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-132408.
Pełny tekst źródłaResearch Funders not listed under Research funders and strategic development areas: Marie Curie actions under the Project No.264613-NetFISiC, the centre of Nano Science and Nano technology (CeNano).
Zhu, Xingguang Williams John R. "Alternative growth and interface passivation techniques for SiO2 on 4H-SiC". Auburn, Ala, 2008. http://hdl.handle.net/10415/1494.
Pełny tekst źródłaChen, Zengjun Williams John R. "Electrical properties of MOS devices fabricated on 4H carbon-face SiC". Auburn, Ala, 2009. http://hdl.handle.net/10415/1858.
Pełny tekst źródłaOmotoso, Ezekiel. "Electrical characterization of process- and radiation-induced defects in 4H-SiC". Thesis, University of Pretoria, 2015. http://hdl.handle.net/2263/53547.
Pełny tekst źródłaThesis (PhD)--University of Pretoria, 2015.
Physics
PhD
Unrestricted
Stone, Stephen E. "A Study of the Effects of Neutron Irradiation and Low Temperature Annealing on the Electrical Properties of 4H Silicon Carbide". The Ohio State University, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=osu1211898142.
Pełny tekst źródłaShort, Eugene L. "Sequential afterglow processing and non-contact Corona-Kelvin metrology of 4H-SiC". [Tampa, Fla] : University of South Florida, 2009. http://purl.fcla.edu/usf/dc/et/SFE0003102.
Pełny tekst źródłaNegoro, Yuki. "Ion implantation and embedded epitaxial growth for 4H-SiC power electronic devices". 京都大学 (Kyoto University), 2005. http://hdl.handle.net/2433/144921.
Pełny tekst źródłaShort, Eugene L. III. "Sequential Afterglow Processing and Non-Contact Corona-Kelvin Metrology of 4H-SiC". Scholar Commons, 2009. https://scholarcommons.usf.edu/etd/19.
Pełny tekst źródłaDi, Benedetto Luigi. "Analysis and design of 4H-SiC bipolar mode field effect power (BMFET)". Doctoral thesis, Universita degli studi di Salerno, 2013. http://hdl.handle.net/10556/894.
Pełny tekst źródłaAnalysis and design of a new Silicon Carbide polytype 4H (4H-SiC) bipolar power transistor are the main topics of this Ph.D. thesis. The device is the Bipolar Mode Field Effect Transistor (BMFET) and exploits the electric field due to the channel punching-through in order to have a normally-off behavior and the minority carrier injection from the gate regions into the channel in order to obtain the channel conductivity modulation. The structure of the transistor is oxide-free and its advantages are due to the lower conduction resistance, to the higher output current density and blocking voltage and to the elevated switching frequency, which make it competitive with commercial 4H-SiC Junction Field Effect Transistors or Bipolar Junction Transistors. These activities, which have been completed with the definition of the main process steps and of the mask layouts, are supported by a technology activity and by an intense modeling activity of BMFET electrical characteristics, which has been validated by comparisons with the results of numerical simulator (ATLAS Silvaco) and the measures of commercial devices having a similar structure, like Vertical-JFETs. In the former activity, in order to obtain an integrated free-wheeling diode in anti-parallel configuration to BMFET, an original 4H-SiC Schottky rectifier has been fabricated; precisely, for the first time in the literature, DiVanadium PentOxide (V2O5), a Transition Metal Oxide, has been used as anode contact of the rectifier. The device is a heterojunction between a thin V2O5 layer, which is thermally evaporated and has a thickness of around 5nm, and a 4H-SiC n-type low doped epilayer. By analyzing the JD-VD and CD-VD curves, the structure has a rectifier behavior with a high/low current ratio higher than seven order of magnitude and its transport mechanism is described by the thermionic emission theory characterized by a Schottky barrier height and an ideality factor between 0.78eV and 0.85eV and between 1.025 and 1.06, respectively, at T=298K. Because the gate doping concentration greatly influences the BMFET performances, as input resistance, DC current gain and blocking voltage, Aluminum ion implantation process, used to realize the Gate regions, is strongly analyzed in terms of the dose concentrations and of the annealing temperature. It will show as the necessity of a low BMFET on-resistance, which is possible with highly conductive gate regions in order to permit high injection levels of the minority carriers, is counteracted by the Aluminum incomplete ionization in 4H-SiC. This phenomenon together with the band-gap narrowing effect limits the hole carrier density from gate to channel. The analysis, in collaboration with the Institute for the Microelectronics and Microsystems (IMM) of CNR in Bologna, Italy, consists to reveal the effects of various different doses at different temperature annealing (1920K and 2170K) on the gate injection efficiency and on the input current density. Since the introduction of the first normally-off Si JFET in ‘80 years, the description of the potential barrier height into the channel has been unresolved due to the complex relations with the channel geometry and bias conditions. In the second activity an analytical model of the potential barrier height in the channel is proposed and compared with the numerical simulation results by changing the channel length and width, respectively in the range 0.1÷6μm e 0.5÷3μm, the channel doping concentration, between 1014÷1017cm-3, and the output and input bias voltages. Moreover, it has been also validated by using Silicon as semiconductor material, permitting to extend it to other devices with similar structures, like BSITs, VJFETs and SITs. From a further improvement of this model, another has been developed, which is able to describe the trans-characteristics of the transistor both in sub-threshold condition and in unipolar conduction, and the comparisons with numerical simulations and experimental data validated the results. Finally, the analysis of the input diode during the switching-off has been performed because the switching capability of the BMFET depends on the storage charge into the channel during the “on” state. The result is the development of an analytical model that describes the spatial distributions of the electric field, of the minority carrier concentration and of the carrier current densities into the epilayer at each instant during the switching, in addition obviously to the current and voltage transients. It is shown as the combination of this model with another static model just developed in a previous Ph.D. thesis is an useful instrument to understand how physical parameters, which are dependent on the manufacturing processes, as carrier life-time and doping concentrations, can affect the dynamic behavior. [edited by author]
XI n.s.
Maslougkas, Sotirios. "Gate oxide characterization of 4H-SiC MOS capacitors : A study of the effects of electrical stress on the flat-band voltage of n-type substrate 4H-SiC MOS capacitors". Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-301848.
Pełny tekst źródłaKisel är det viktigaste materialet som används i elektronik. Utvecklingen av kraftelektronik och behovet av mer energieffektiva halvledarkomponenter ledde kisel till sina gränser. Kiselkarbid är ett lovande material för elektroniska applikationer med ett brett bandgap, högt kritiskt elektriskt fält, hög värmeledningsförmåga och hög mättningshastighet. Förutom dess överlägsenhet gentemot kisel, kommer kiselkarbid med en nackdel med cirka två storleksordningar fler gränssnittsfällor i SiC / SiO2-gränssnittet jämfört med kisel. Ett resultat av denna nackdel är en förskjutning av flatbands-spänningen, VFB, när man applicerar en spänning på gaten till MOS-kondensatorer och kraft- MOSFETar. För att studera de rena egenskaperna hos SiC/SiO2-gränssnittet har två spänningsmetoder, en strömpulsstress och ett uppåtriktat gate-spänningssvep, applicerats på 4H-SiC- kondensatorer med nitriderade termiska oxider vid rumstemperatur och vid högre temperaturer. Återställning av VFB undersöktes. VFB kan återställas vid rumstemperatur med ett nedåtriktat gate-spänningssvep medan en återställning inte behövs vid högre temperaturer. Den maximala spänningen (initialspänningem) och svephastigheten för det nedåtriktade svepet undersöktes och högre initialspänningar och lägre svephastigheter visade sig leda till bättre VFB-återställning. En 200 millisekund lång strömpuls-stress implementerades och den hade nästan samma effekter som ett uppåtriktat spänningssvep
Nguyen, Tuan Khoa. "Piezoresistive Effect in 4H Silicon Carbide towards Mechanical Sensing in Harsh Environments". Thesis, Griffith University, 2018. http://hdl.handle.net/10072/381509.
Pełny tekst źródłaThesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Eng & Built Env
Science, Environment, Engineering and Technology
Full Text
Grivickas, Paulius. "Optical studies of carrier transport and fundamental absorption in 4H-SiC and Si". Doctoral thesis, KTH, Microelectronics and Information Technology, IMIT, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3695.
Pełny tekst źródłaThe Fourier transient grating (FTG) technique and a novelspectroscopic technique, both based on free carrier absorption(FCA) probing, have been applied to study the carrierdiffusivity in 4H-SiC and the fundamental absorption edge in4H-SiC and Si, respectively.
FTG is a unique technique capable of detecting diffusioncoefficient dependence over a broad injection interval rangingfrom minority carrier diffusion to the ambipolar case. In thiswork the technique is used for thin epitaxial 4H-SiC layers,increasing the time- and spatial-resolution of the experimentalsetup by factors of ~100 and ~10, respectively, in comparisonto the established Si measurements. It is found that thediffusion coefficient within the detected excitation range inn-type 4H-SiC appears to be lower than the analyticalprediction from Hall-mobility data. To explain this, it issuggested that the minority hole mobility is reduced withrespect to that of the majority one or that the hole mobilityvalue is in general lower than previously reported. Observeddifferences between the temperature dependency of the ambipolardiffusion and the Hall-prediction, on the other hand, areattributed to the unknown Hall factor for holes and theadditional carrier-carrier scattering mechanism in Hallmeasurements. Furthermore, at high excitations a substantialdecrease in the ambipolar diffusion is observed andadditionally confirmed by the holographic transient gratingtechnique. It is shown that at least half of the decrease canbe explained by incorporating into the theoretical fittingprocedure the calculated band-gap narrowing effect, taken fromthe literature. Finally, it is demonstrated that numerical datasimulation can remove miscalculations in the analytical Fourierdata analysis in the presence of Auger recombination.
Measurements with variable excitation wavelength pump-probeare established in this work as a novel spectroscopic techniquefor detecting the fundamental band edge absorption in indirectband-gap semiconductors. It is shown that the techniqueprovides unique results at high carrier densities in doped orhighly excited material. In intrinsic epilayers of 4H-SiC,absorption data are obtained over a wide absorption range, atdifferent temperatures and at various polarizations withrespect to the c-axis. Experimental spectra are modeled usingthe indirect transition theory, subsequently extracting thedominat phonon energies, the approximate excitonic bindingenergy and the temperature induced band-gap narrowing (BGN)effect in the material. Measurements in highly dopedsubstrates, on the other hand, provide the first experimentalindication of the values of doping induced BGN in 4HSiC. Thefundamental absorption edge is also detected in highly dopedand excited Si at carrier concentrations exceeding theexcitonic Mott transition by several orders of magnitude. Incomparison to theoretical predictions representing the currentunderstanding of absorption behavior in dense carrier plasmas,a density dependent excess absorption is revealed at 75 K.Summarizing the mainfeatures of the subtracted absorption, itis concluded that an excitonic enhancement effect is present inSi.
Wutikuer, Otkur. "Fabrication and Characterization of 4H-SiC MOS Capacitors with Different Dielectric Layer Treatments". Thesis, Linköpings universitet, Halvledarmaterial, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-144984.
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