Dissertations / Theses on the topic 'Vacuum annealing'

Stainless steel family grades are very famous for their combined corrosion resistance and high mechanical properties. These properties can be improved further by decreasing the content of impurities like carbon and oxygen. The main purpose of this research work is to study the possibility of stainless steel powder decarburization by vacuum annealing. The influence of different process parameters like treatment time, temperature, fraction size and depth of the powder layer on the decarburization process was analyzed. The investigation results showed that it is possible to achieve extra low values of carbon and oxygen in steel powder by processing it with optimum process parameters.

Thin-film solar cells on glass substrates are likely to have a bright future due to the potentially low costs and the short energy payback times. Polycrystalline silicon (poly-Si, grain size > 1 pm) has the advantage of being non-toxic, abundant, and long-term stable. Glass as a substrate, however, limits the processing temperatures to ~600??C for longer process steps. Films with large grain size can be achieved by solid phase crystallisation (SPC), and especially by solid phase epitaxy (SPE) on seed layers, using amorphous silicon deposited at low temperatures as a precursor film. With SPC and SPE, the amorphous silicon film is typically crystallised at ~600??C over hours. During this anneal at atmospheric pressure -depending on the properties of the amorphous silicon film- ambient gas can percolate the film and can negatively affect the crystallisation. In this work, a high-vacuum anneal chamber was designed and built to allow the in-situ crystallisation of amorphous silicon films deposited on glass in a PECVD cluster tool. An important aspect of the design was the comfortable and safe operation of the vacuum anneal chamber to enable unattended operation. This was realised by means of a state-of-the-art, programmable temperature controller and a control circuit design that incorporates various safety interlocks. The chamber interior was optimised such that a temperature uniformity of 2-3K across the sample area was achieved. The chamber was calibrated and tested, and SPC and SPE samples were successfully crystallised. In initial SPC crystallisation experiments with solar cell structures, after post-deposition treatments, a 1 -sun open-circuit voltage of 465 mV was obtained, similar to furnace-annealed samples. In initial experiments with SPE solar cell structures, difficulties regarding the characterisation of the unmetallised solar cells with the quasi-steady-state open-circuit voltage method (QSSVOC) were encountered after post-deposition hydrogen treatment. A possible explanation for these difficulties is the contact formation with the metal probes. Furthermore, limiting factors of the QSSVOC method for the characterisation of unmetallised cells with high contact resistance values were investigated and, additionally, the accuracyof the QSSVOC setup was improved in the low light intensity range.

Для изучения электрофизических свойств широкозонных полупроводников собран модуль оптической стимуляции в микрозондовой станции CascadeMicrotechMPS150.Стимуляция производится светом полупроводникового лазера с длиной волны 532 нм. Управление лазером производится непосредственно из программы измерения характеристик материалов (написанной в среде LabView) и позволяет изменять мощность от 2 до 225 мВт/с путем изменения скважности управляющих импульсов. Разработан и собран модуль подогрева образца в микрозондовой станции CascadeMicrotechMPS150.Модуль имеет независимое от измерительного тракта управление нагревом и позволяет нагревать образец до 120 °С за 7,5 мин и поддерживать температуру образца с точностью до 0,1 °С. Разработан и собран модуль высокотемпературного отжига материалов. Модуль состоит из двух независимых блоков нагрева (950 ° С и 1300 °С)и позволяет производить отжиг материалов в вакууме и различных газовых средах. Максимальные размеры образца‒(Д х В х Ш, мм) –50х10х10, скорость нагрева в первом блоке до 950°С ‒7.5 мин., во втором до 1200°С‒103 минуты.
To study the electrophysical properties of wide-gap semiconductors, an optical stimulation module was assembled in a Cascade Microtech MPS 150 microprobe station. Stimulation is performed by the light of a semiconductor laser with a wavelength of 532 nm. The laser is controlled directly from the program for measuring the characteristics of materials (written in the LabView environment) and allows you to change the power from 2 to 225 mW / s by changing the duty cycle of the control pulses. A sample heating module was developed and assembled in the Cascade Microtech MPS 150 microprobe station. The module has heating control independent of the measuring path and allows heating the sample to 120 ° C in 7.5 minutes and maintaining the temperature of the sample with an accuracy of 0.1 ° C.A module for high‒temperature annealing of materials was developed and assembled. The module consists of two independent heating units (950 ° C and 1300 ° C) and allows annealing of materials in vacuum and various gaseous media. The maximum dimensions of the sample ‒ (L x W x H, mm) are 50x10x10, the heating rate in the first block to 950 ° C is 7.5 minutes, in the second to 1200 ° C for 103 minutes.

Graphene, a two-dimensional counterpart of three-dimensional graphite, has attracted significant interest, due to its distinctive electrical and mechanical properties, for developing electronic, optoelectronic, and sensor technologies. In general, doping of graphene is important, as it gives rise to p-type and n-type materials, and it adjusts the work function of the graphene. This adjustment is necessary in order to control charge injection and collection in devices such as solar cells and light emitting devices. Current methods for graphene doping involve high temperature process or interactions with chemicals that are not stable. Moreover, the process of transferring graphene from its growth substrate and its exposure to the environment results in a host of chemical groups that can become attached to the film and alter its electronic properties by accepting or donating electrons/holes. Intentional and controllable doping of the graphene, however, requires a deeper understanding of the impact of these groups. The proposed research will attempt to clarify the unintentional doping mechanism in graphene through adsorption or desorption of gas/vapor molecules found in standard environments. A low temperature, controllable and defect-free method for doping graphene layers will also be studied through modifying the interface of graphene and its support substrate with self-assembled monolayers (SAMs) which changes the work function and charge carriers in the graphene layer. Furthermore, current methods of chemical vapor deposition synthesis of graphene requires the film to be transferred onto a second substrate when the metal layer used for growth is not compatible with device fabrication or operation. To address this issue, the proposed work will investigate a new method for wafer scale, transfer-free synthesis of graphene on dielectric substrates using new carbon sources. This technique allows patterned synthesis on the target substrate and is compatible with standard device fabrication technologies; hence, it opens a new pathway for low cost, large area synthesis of graphene films.

Les couches epitaxiees a basse temperature (<650c) offrent des perspectives interessantes en vue de la fabrication de dispositifs microelectroniques sophistiques, integrant des structures fragiles comme des profils de dopants tres minces ou des films heteroepitaxies metastables. Ces couches doivent etre structuralement parfaites afin d'atteindre les caracteristiques electriques attendues. Ce travail est motive par l'etude de la morphologie de surface de couches epitaxiales de si et si#1#-#xge#x deposees sur si(100) par cvd a basse temperature (550-800c). La caracterisation physique a principalement ete effectuee par microscopie a force atomique (afm). La preparation de surface des substrats avant epitaxie est une etape critique. C'est pourquoi la surface du si(100) a ete etudiee apres nettoyage par voie humide et apres recuit sous hydrogene vis a vis de la nano-rugosite, des terminaisons atomiques et des contaminants adsorbes. Les premiers instants de l'homoepitaxie de si ont ete etudies en detail. Deux modes de croissance (l'un lisse l'autre rugueux) dependant a la fois des parametres de substrat et de depot sont observes. Le mode lisse se caracterise par une croissance en terraces, alors que le mode rugueux correspond a une croissance par facettage. La morphologie de surface resultante a ete reliee a la couverture dynamique en hydrogene du front de croissance. D'autres mecanismes de croissance entrent en jeu dans les films si#1#-#xge#x en raison des contraintes existantes. Des films de si#1#-#xge#x contraints en compression et en tension ont ete etudies. Les films en compression presentent une croissance stranski-krastanov sans defaut permettant une relaxation partielle de la contrainte au travers d'ondulations de surface. Pour les films en tension, la topographie finale depend fortement de la diffusion de surface des ad-atomes.

碩士
國立成功大學
物理學系碩博士班
96
In this work, we synthesize nanocomposite under ultra-high vacuum which has high density defects. We observe little change to magnetoresistance（MR）when samples were annealing under ultra high vacuum environment（10-9 torr）. However, apparent change of MR is observed under high vacuum annealing （10-6 torr）. Structure of Co/TiO2 nanocomposite has characterized by XRD and XAS. The change of blocking temperature doesn’t have the corresponding result with MR which indicates that Co particles may not be main reason. Analysis of impedance spectra and temperature-dependent resistivity show that oxide layer have the great influence to the change of MR. In summary, we think that observed magnetoresistance change in different vacuum annealing was attributed to defects.

碩士
大葉大學
電機工程學系
95
ZnO：Fe films were grown by the RF magnetrom sputtering technique. In this work we studied the effects of high-vacuum annealing on the conductivity、carrier concentration、mobility、transmittance and magnetization of ZnO：Fe films. The electron spectroscopy for chemical analyses (ESCA) was used to analyze the chemical states of ZnO：Fe thin films. The sputtering parameters were adjusted and employed to obtain the optimum electro-optical properties of ZnO：Fe thin films. The optimum conditions for the growth of 150-nm thick ZnO：Fe films are obtained with ZnO RF power = 30 W、Fe RF power = 10 W、working pressure = 1 mTorr、annealing pressure=8.5×10-6 torr and annealing temperature of 510 ℃、for 60 mins. As a result, we have successfully achieved the lowest resistivity of 2.24×10-3 Ωcm, and the carrier concentration of 2.78×1021 cm-3 with the mobility of 1.01 cm2/Vs. The average optical transmittance within the visible spectra is higher than 92.35 %. The ESCA analysis reveals that the valence of Fe is triplicate. Moreover, the resistivity is reduced with the increase of the grain size, being consistent with the prediction of grain-boundary-scattering model.

Yeung Chun Fai = 厚度和眞空熱處理對單晶 La0.67Ca0.33MnO3 薄膜特性之影響 / 楊進輝.
Thesis (M.Phil.)--Chinese University of Hong Kong, 2000.
Includes bibliographical references.
Text in English; abstracts in English and Chinese.
by Yeung Chun Fai = Hou du he zhen kong re chu li dui dan jing La0.67Ca0.33MnO3 bo mo te xing zhi ying xiang / Yang Jinhui.
Acknowledgements --- p.i
Abstract --- p.ii
論文摘要 --- p.iv
Table of contents --- p.v
List of Figures --- p.viii
List of Tables --- p.xiii
Chapter Chapter I --- Introduction
Chapter 1.1 --- Development of magnetoresistance materials --- p.1-1
Chapter 1.1.1 --- Magnetoresistance (MR) --- p.1-1
Chapter 1.1.2 --- Anisotropy magnetoresistance (AMR) --- p.1-1
Chapter 1.1.3 --- Giant magnetoresistance (GMR) --- p.1-2
Chapter 1.1.4 --- Colossal magnetoresistance (CMR) in rare-earth manganites --- p.1-3
Chapter 1.1.5 --- Possible origin of CMR in rare-earth manganites --- p.1-4
Chapter 1.1.5.1 --- Double exchange mechanism --- p.1-4
Chapter 1.1.5.2 --- Jahn-teller effect --- p.1-6
Chapter 1.1.5.3 --- Other mechanisms --- p.1-7
Chapter 1.1.6 --- Possible origins of CMR in Thallium manganite pyrochlores (TI2Mn207) --- p.1-7
Chapter 1.2 --- New developments in manganite materials --- p.1-8
Chapter 1.3 --- Our approach --- p.1-8
Chapter 1.3.1 --- Why choose La0 .67Ca0.33Mn03 material? --- p.1-8
Chapter 1.3.2 --- The role of oxygen content in manganite materials --- p.1-9
Chapter 1.4 --- The scope of this thesis work --- p.1-11
References --- p.1-12
Chapter Chapter II --- Instrumentation
Chapter 2.1 --- Thin film deposition --- p.2-1
Chapter 2.1.1 --- Introduction --- p.2-1
Chapter 2.1.2 --- Facing-target sputtering (FTS) --- p.2-3
Chapter 2.1.3 --- Deposition profile calculation for sputtering with FTS --- p.2-4
Chapter 2.1.4 --- Vacuum system --- p.2-7
Chapter 2.2 --- Characterization --- p.2-8
Chapter 2.2.1 --- Profilometer --- p.2-8
Chapter 2.2.2 --- Atomic force microscopy (AFM) --- p.2-8
Chapter 2.2.3 --- X-ray diffraction (XRD) --- p.2-8
Chapter 2.2.4 --- Resistance and magnetoresistance measurement --- p.2-10
Chapter 2.2.5 --- Hall effect measurement --- p.2-11
References --- p.2-13
Chapter Chapter III --- Epitaxial growth of La0.67Ca0.33 Mn03 thin films
Chapter 3.1 --- Introduction --- p.3-1
Chapter 3.2 --- Fabrication and characteristics of LCMO target --- p.3-1
Chapter 3.3 --- Substrate materials --- p.3-5
Chapter 3.4 --- Deposition --- p.3-10
Chapter 3.4.1 --- Sample preparation --- p.3-10
Chapter 3.4.2 --- Substrate temperature --- p.3-10
Chapter 3.4.3 --- Deposition process --- p.3-17
Chapter 3.5 --- Post-annealing effect --- p.3-18
Chapter 3.6 --- Film composition analysis --- p.3-22
Chapter 3.7 --- Epitaxial growth examination --- p.3-22
References --- p.3-27
Chapter Chapter IV --- Thickness effect in single-crystal LCMO thin films grown on NGO and STO
Chapter 4.1 --- Motivation --- p.4-1
Chapter 4.2 --- Resistance measurement --- p.4-2
Chapter 4.3 --- Magnetoresistance (MR) --- p.4-8
Chapter 4.4 --- Crystal structure --- p.4-12
Chapter 4.5 --- Surface morphology --- p.4-16
Chapter 4.6 --- Hall effect measurement --- p.4-19
Chapter 4.6.1 --- Basic principle --- p.4-19
Chapter 4.6.2 --- Experiment --- p.4-20
Chapter 4.6.3 --- Carrier concentration & mobility --- p.4-20
Chapter 4.7 --- Discussions --- p.4-25
References --- p.4-27
Chapter Chapter V --- Strain dependent vacuum annealing effectin single-crystal La0.67Ga0.33MnO3 thin films
Chapter 5.1 --- Motivation --- p.5-1
Chapter 5.2 --- Sample description --- p.5-1
Chapter 5.3 --- Vacuum annealing process --- p.5-2
Chapter 5.4 --- Crystal structure --- p.5-2
Chapter 5.5 --- Resistance measurement --- p.5-6
Chapter 5.6 --- Discussions --- p.5-8
Chapter 5.6.1 --- Lattice expansion --- p.5-8
Chapter 5.6.2 --- Determination of oxygen content --- p.5-9
References --- p.5-11
Chapter Chapter VI --- Activation energy of small polaron in La0.67Ca0.33MnO3 thin films
Chapter 6.1 --- Motivation --- p.6-1
Chapter 6.2 --- Basic theory --- p.6-1
Chapter 6.2.1 --- Variable range hopping --- p.6-1
Chapter 6.2.2 --- Semiconduction --- p.6-2
Chapter 6.2.3 --- Nearest-neighbor hoping of small polarons --- p.6-2
Chapter 6.3 --- Sample description --- p.6-3
Chapter 6.4 --- Resistance measurement --- p.6-4
Chapter 6.5 --- Activation energy --- p.6-4
Chapter 6.6 --- Discussions --- p.6-5
References --- p.6-12
Chapter Chapter VII --- Conclusions --- p.7-1

Lee Wai Tak Joseph = Fe₃₋xZnxO₄的真空熱處理效應及磁隧道結 / 李懷德.
On t.p. "-x" and "x" is subscript.
Thesis (M.Phil.)--Chinese University of Hong Kong, 2006.
Includes bibliographical references.
Text in English; abstracts in English and Chinese.
Lee Wai Tak Joseph = Fe₃₋xZnxO₄ de zhen kong re chu li xiao ying ji ci sui dao jie / Li Huaide.
Acknowledgement --- p.i
Abstract --- p.ii
論文摘要 --- p.iii
Table of contents --- p.iv
List of Figures --- p.ix
List of Tables --- p.xiv
Table of Contents
Chapter Chapter 1 --- Introduction
Chapter 1.1 --- Introduction to Magnetite Fe3O4 and Zinc Ferrite Fe3.-xZnxO4 --- p.1-1
Chapter 1.1.1 --- Crystal structure and Properties of Fe304 and Fe3-xZnxo4 --- p.1-1
Chapter 1.1.2 --- Transformation of Iron Oxides --- p.1-6
Chapter 1.2 --- Verwey transition --- p.1-10
Chapter 1.2.1 --- Introduction --- p.1-10
Chapter 1.2.2 --- Charge-orbital ordering --- p.1-15
Chapter 1.3 --- Trilayer Magnetic Tunneling Junction (MTJ) --- p.1-18
Chapter 1.3.1 --- Half-metallic Fe3O4 --- p.1-18
Chapter 1.3.2 --- Tunneling Magnetoresistance (TMR) --- p.1-19
Chapter 1.4 --- Research Motivation --- p.1-20
Chapter 1.5 --- Scope of this thesis --- p.1-21
References --- p.1-22
Chapter Chapter 2 --- Instrumentation
Chapter 2.1 --- Sample Preparation --- p.2-1
Chapter 2.1.1 --- Vacuum System --- p.2-1
Chapter 2.1.2 --- Facing-target Sputtering (FTS) Technique --- p.2-3
Chapter 2.2 --- Sample Treatment --- p.2-7
Chapter 2.2.1 --- Vacuum Annealing (VA) --- p.2-7
Chapter 2.2.2 --- Silver Electrode Coating System --- p.2-9
Chapter 2.3 --- Sample Characterization --- p.2-11
Chapter 2.3.1 --- Four-point-probe DC Resistivity Measurement --- p.2-11
Chapter 2.3.2 --- Current-Voltage Measurement (IV) --- p.2-11
Chapter 2.3.3. --- X-ray Diffraction (XRD) --- p.2-13
Chapter 2.3.4 --- X-ray Fluorescence (XRF) Method --- p.2-14
Chapter 2.3.5 --- Alpha-step Surface Profiler --- p.2-14
Chapter 2.3.6 --- Atomic Force Microscope (AFM) --- p.2-15
References --- p.2-16
Chapter Chapter 3 --- Fabrication of Fe3- xZnxO4Thin Films
Chapter 3.1 --- Thin Film Deposition --- p.3-1
Chapter 3.1.1 --- Review of Deposition Procedures --- p.3-1
Chapter 3.1.2 --- Preparation of Substrates --- p.3-6
Chapter 3.1.3 --- Deposition of Fe3-xZnxO4 thin films --- p.3-7
Chapter 3.2 --- Characterization of Fe3-xZnxO4 thin films --- p.3-9
Chapter 3.2.1 --- Surface Morphology --- p.3-9
Chapter 3.2.2 --- Temperature-Dependent Resistivity Measurement --- p.3-11
Chapter 3.3 --- Factors affecting the Quality of films --- p.3-18
Chapter 3.3.1 --- Effect of Substrates --- p.3-18
Chapter 3.3.2 --- Effects of Sputtering Power --- p.3-21
Chapter 3.3.3 --- Effects of Temperature --- p.3-24
Chapter 3.3.4 --- Effects of Thickness --- p.3-29
Chapter 3.4 --- Chapter summary --- p.3-32
References --- p.3-33
Chapter Chapter 4 --- Vacuum Annealing of Fe3-xZnxO4 Thin Films
Chapter 4.1 --- Introduction --- p.4-1
Chapter 4.2 --- Post-Annealing Effect in the Presence of Oxygen --- p.4-6
Chapter 4.3 --- Vacuum Annealing of Fe3-xZnx04 thin films --- p.4-12
Chapter 4.3.1 --- First Stage of Vacuum Annealing --- p.4-12
Chapter 4.3.2 --- Second Stage of Vacuum Annealing --- p.4-17
Chapter 4.3.3 --- Third Stage of Vacuum Annealing --- p.4-25
Chapter 4.4 --- Chapter summary --- p.4-32
References --- p.4-33
Chapter Chapter 5 --- Trilayer Magnetic Tunneling Junction (MTJ)
Chapter 5.1 --- Introduction --- p.5-1
Chapter 5.2 --- Fabrication of Trilayer Magnetic Tunneling Junction --- p.5-3
Chapter 5.3 --- Tunneling Magnetoresistance (TMR) --- p.5-5
Chapter 5.3.1 --- Current-Voltage Characteristic Curve (IV curve) --- p.5-5
Chapter 5.3.2 --- Magnetoresistance Measurement --- p.5-8
References --- p.5-10
Chapter Chapter 6 --- Conclusions
Chapter 6.1 --- Conclusions --- p.6-1
Chapter 6.2 --- Further research --- p.6-2
References --- p.6-3

碩士
大同大學
光電工程研究所
96
Carbon nanotubes (CNTs) give impetus to the research of carbon-based materials because of their singular properties for numerous fields, especially for the application of electronic devices. Multi-walled carbon nanotubes (MWNTs) synthesized by low temperature chemical vapor deposition (CVD) method have defects which can affect electrons transport and reduce the conductivity. In this thesis, vacuum arc rapid thermal annealing (VARTA) approach proposed to reduce the defect structures of MWNTs is to substitute the conventional furnace annealing. Two topics were investigated; Firstly, the defected MWNTs were annealed by heating and cooling in several cycles rapidly. The process is controlled by heating of vacuum arc and cooling of high flow Ar purging. The imperfect structures can be annealed out with high arc current, high flow of Ar, and annealing cycles. Secondly, the oxygen effect of defected MWNTs was studied. The MWNTs were annealed in the chamber which filled with water in low vacuum environment. Besides, we even added Al2O3 powder mixed with samples to discuss the oxidation of MWNTs. The results indicated that the oxygen played an important part to modify the defects in the MWNTs. According to the results found from Raman spectra, the ratio of intensity of G-band peak to that of D-band peak increased by VARTA process and oxidation. The morphology of MWNTs was characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM).

碩士
國立成功大學
材料科學及工程學系
87
Abstract Effects of pulsed KrF laser annealing and vacuum annealing on the preferred orientation, microstructures, and electrical resistivity of Cu films deposited on TiN/Si and TiN/SiO2/Si by electron gun (E-gun) and sputtered gun were studied respectively. Upon puled KrF laser annealing the (111) preferred orientation of Cu films deposited by E-gun evaporation was enhanced, while that of Cu films deposited by sputtering was degraded. The possible reason may be attributed to the larger amounts of oxygen present in the Cu films deposited by sputtering. The TiN films grown on Si at higher temperatures such as 400℃ had (200) preferred orientation which somewhat degraded the (111) preferred growth of Cu film by pulsed KrF laser annealing. In the present study, for the Cu films 1000-3500Å thick annealed at an energy density of 0.3-0.8 J/cm2 the electrical resistivity in the range of 2.3-2.4 μΩ-cm and the (111) texture coefficient(TC) in the range of 1.64-1.74 could be obtained. In addition, the laser-annealed Cu films were very smooth without voids. Upon vacuum annealing the (111) preferred orientation of Cu films could not be improved, meanwhile significant amounts of voids were still present in them.

碩士
國立臺南大學
綠色能源科技學系碩士班
103
Perovskite is very suitable for application in absorbers of the organic solar cell. It has a unique photovoltaic properties, more longer electron - hole transport diffusion lengths and their bipolar charge transport capabilities. Since 2009, the first research of perovskite materials used in solar cells has been a few years, it has become the most solar hot bare hands research material. In this article, we use the electrospray preparation of perovskite-absorbing layer, this method can be applied in large areas of production. After sprayed the precursor solution mixed of PbCl2 and CH3NH3I on the substrate, we make use of vacuum assist process to remove the byproduct (MACl). Than, we are able to obtain pore-free and well crystallized pure triiodide (CH3NH3PbI3) perovskite films. And by changing the heat treatment temperature and concentration, to find out the best production conditions for solar cell perovskite. Finally, we prepare a device with conversion efficiency up to 7.4%, open circuit voltage 0.781 V, a short circuit current 21.41 mA / cm2, Fill factor 0.44. Keyword: Perovskite solar cell、Electrospray preparation、Vacuum assist process.

碩士
國立成功大學
材料科學(工程)學系
86
Interfacial reactions of Co/Si0.76Ge0.24 and Co(Si0.76 Ge0.24)/Si0.76Ge0.24 by vacuum annealing and pulsed KrF laser annealing as afunction o energy density and pulsed number were studied. For the Co/Si0.76Ge0.24 samples annealing at 350℃ segregated to the underlyingSi0.76Ge0.24 film. Above 550℃ the island structure of Ge-dificient germanosilicide grains suuounded by the Ge-rich Si1-xGex at an energydensity of 0.2-0.6 J/cm2 appear three germanosilicide layers, i.e.,nanocrystal and/ or amorphous structure, Co(Si1-xGex), and Co(Si1-xGex)2,wrer formed along the depth direction. At 0.3 J/cm2 Ge reacted region was transformed to a single layer of Co(Si1-xGex)2, while Ge diffused to the Si substrate. At 1.0 J/cm2 constitutional supercooling appeared. Annealingat 0.2 J/cm2 for 20 pulsed could produce a smooth and nearly pure Co(0.76Ge0.24)2 film without inducing Ge segregation out of the germano-silicide hence strain relaxation. For the Co(Si0.76Ge0.24)/Si0.76Ge0.24sample annealed at an energy density of 0.4-0.6 J/cm2 two layers, i.e., Co(Si1- xGex0 and Co(Si1-xGex)2 were formed alepth direction. At1.0 J/ cm2 a single layer of nearly pure Co(Si0.76Ge0.24)2 was formed concurrently with Ge segregation to the Si substrate. Constititional super-cooling occured at 1.6 J/cm2. The energy densities at which either Ge diffusion to the underlying Si substrate or constitutional supecooling occured were higher for Co(Si0.76Ge0.24) than Co.

碩士
國立交通大學
電子研究所
108
In this thesis, firstly, the HfO2/SiGe gate stack with NH3 plasma treatment for interfacial layer was investigated. The high quality interfacial layer was formed and the low interface trap density value (2.3 ×1011 eV-1cm-2) was extracted. The XPS analysis showed that the desired GeOx-free interfacial layer was formed with NH3 plasma treatment. However, the interface quality and thermal stability of the gate stack degraded when we scaled down the EOT by thinning the HfO2 thickness. According to the XPS analysis, the oxide regrowth after annealing was observed. In order to enhance the thermal stability, the NH3 plasma treatment was adopted on HfO2. However, the improvement was not enough and limited when the PMA temperature exceeded 400 C. In addition to the normal pressure N2 annealing, we employed the high-vacuum annealing on SiGe gate stack during PMA to clarify the O source of oxide regrowth. The obvious improvement on SiGe gate stack with PMA in high-vacuum was observed and the scalable SiGe gate stack with the lowest Dit value (1.8 ×1011 eV-1cm-2) was achieved at 500 C PMA. Base on the electrical characteristics and material analysis, we illustrated the possible interaction to explain the experimental results. During the thermal process, the O2 in environment could penetrate to the SiGe surface, which led to undesired oxide regrowth and even the relaxation of strained SiGe layer, resulting in high Dit value. Moreover, the crystallization of high-κ layer could make the O2 penetration easier and aggravated the oxide regrowth and SiGe layer relaxation. Finally, the SiGe p-MOSFETs with HfO2/HfON/p-SiGe gate stack were fabricated. The device with PMA in normal pressure N2 at 300 C demonstrated the best subthreshold swing about 232 mV/decade and the device with PMA in at high-vacuum at 500 C showed the best Ion/Ioff ratio about 8.9×104. According to the comparison of gd verses VG-Vth, the device with PMA in normal pressure N2 at 300 C demonstrated the highest mobility value. However, the extracted mobility value was not as high as expected. Based on the experimental results, the interface quality of SiGe gate stack was sensitive to the process environment. Therefore, we speculated that the low mobility value could be due to the interface degradation resulted from the subsequent processes in device fabrication.

碩士
雲林科技大學
化學工程與材料工程研究所
98
Characteristics of electrochemical capacitors include higher energy density, higher power density, and longer life cycle. They can be applied in 3C (Computer, Communication, Consumptive electronic product) and the quality, reliability and cost competition advantage of 3C products can be improved. Thus their manganese-cobalt-zinc oxide electrodes will be sputtered by radio frequency (RF), in this study. First, in order to increase adhesion of manganese-cobalt-zinc oxide thin films with different substrate temperatures and bias voltages. Next, will be annealed by oxygen-vacuum treatment with different annealing temperatures. Finally, the electrodes will be tested by XRD, FE-SEM, AFM, XPS, and scratch testing, etc.. In addition, in order to find better sputtering conditions (substrate temperature and bias voltage) and oxygen-vacuum annealing temperature conditions, the cyclic voltammetry (CV) will be taken for the electrodes.

碩士
崑山科技大學
電機工程研究所
101
In this study, we used RF magnetron co-sputtering to grow IGZO films on glass substrates. The films were processed by changing work pressure, process time, and RF power to get appropriate properties of films. After deposition, the IGZO samples were treated in various atmosphere plasma and vacuum annealing. After the atmosphere plasma and vacuum annealing treatment, the IGZO properties could further improve such as transmittance and resistivity. According to the experiment results, better properties of IGZO films were obtained at lower work pressure. When the deposition time is too long the electrical and optical properties will become worse. The resistance and transmittance of films were improved with increasing the gallium-doped as well as increasing the RF power. For the Ga2O3 power of 100W, the best properties of the resistivity of 1.17×10-3 Ω-cm, carrier concentration of 2.01×1020 cm-3, mobility of 26.5 cm2/Vs and average transmittance of 90.4 % were obtained at the process condition which was carried out at that the work pressure is 3mtorr, the IZO power is 125W and, the deposition time is 20min and the substrate temperature is set at room temperature. For the Ga2O3 power of 30W, we can get the best properties with Ga2O3 doped. The best properties show the resistivity of 7.95×10-4 Ω-cm, the carrier concentration of 1.8×1020 cm-3, the mobility of 43.6 cm2/Vs and the average transmittance of 87.7 %. In vacuum annealing, we got the best properties of films at temperature of 400℃ and processing time of 60min. The heating effect by vacuum annealing into IGZO film was eliminate defects and ion diffusion in high temperature, therefore the properties were improved such as the resistivity of 3.621×10-4 Ω-cm, the carrier concentration of 4.038×1020 cm-3, the mobility of 42.7 cm2/Vs and the average transmittance of 90.36 %. In different atmosphere plasma, we got the transmittance increased without changing the resistivity on Argon plasma, and the transmittance was changed a little. The results show that the resistivity was reduced in hydrogen plasma, transmittance and resistivity but changes a little in nitrogen and argon plasma.

The formation of the micro- and nanodomain structures during polarization reversal has been studied in single crystal lithium niobate with inhomogeneously modified conductivity. It is well known that the vacuum annealing and plasma-source ion irradiation of the lithium niobate crystals leads to sufficient increase of the bulk conductivity due to out-diffusion of the oxygen from the sample surface. Creation of layers with modified conductivity leads to inhomogeneous distribution of applied electric field in bulk of ferroelectric crystals. Polarization reversal in such a crystals permits to localize charged domain walls in the bulk. Methods of creation of charged domain walls can be used for the construction of the waveguide structures, optical modulators and resonators. The main conclusions of the work: 1) It was shown that plasma-source ion irradiation and vacuum annealing leads to inhomogeneous change of absorption and increase of the conductivity, which can be attributed to the out-diffusion of oxygen and lithium segregation in the surface layer of crystal. 2) Inhomogeneous distribution of electric field in the bulk of modified crystals leads to significant decrease of switched layer thickness. 3) Effect of formation and growth of non-through domains with charged domain walls has been revealed. 4) Analysis of switching current by modified Kolmogorov-Avraami formula permit to determine mobility of domain wall and threshold filed of polarization reversal.
Целью работы являлось экспериментальное исследование формирования микро- и нанодоменных структур в монокристаллах ниобата лития с неоднородно модифицированной проводимостью. Известно, что обработка воздействием низкоэнергетичного ионно-плазменного облучения и восстановительного отжига приводит к резкому увеличению проводимости кристаллов за счёт аут-диффузии кислорода с поверхности. Создание слоёв с измененной проводимостью приводит к неоднородному распределению электрического поля в объёме сегнетоэлектрических кристаллов, что позволяет создавать внутри-объёмные заряженные доменные структуры при переключении поляризации. Методы создания заряженных доменных структур используются для создания элементов интегральных оптических устройств: волноводных структур, оптических модуляторов и резонаторов. Основные выводы работы: 1) Показано, что ионно-плазменное облучение и восстановительный отжиг кристаллов приводят к неоднородному изменению поглощения и увеличению проводимости, что может быть отнесено за счёт аут-диффузии кислорода и сегрегации лития в поверхностном слое. 2) Установлено, что неоднородное распределение электрического поля в объёме модифицированных кристаллов приводит к значительному понижению порогового поля переключения поляризации, за счёт уменьшения толщины переключаемого слоя. 3) Впервые обнаружен и изучен эффект формирования и роста несквозных доменов с заряженными доменными стенками. 4) Анализ тока переключения модифицированной формулой Колмогорова-Аврами позволил определить подвижность доменной стенки и пороговое поле начала переключения.

碩士
國立成功大學
材料科學(工程)學系
86
Abstract-The interfacial reactions of Pd/Si0.76Ge0.24 were studiedby pulsed KrF laser annealing as a function of energy densityand pulsed number. At an energy density of 0.1-0.2 J/cm2 a continuous germanosilicide layer commpossed of a low temperature phase, Pd2(Si1-xGex), and a high tempperature phase, Pd(Si1-xGex),was formed. In contrast to vacuum annealing Ge segregation out of the germanosilicide layer and the strain relaxation of the residualSi0.76Ge0.24 film could be effectively suppressed by pulsed KrF laserannealinng at 0.1 J/cm2. Multiple pulse annealing at 0.1 J/cm2 could further homogenize the Pd concentraation of the germanosilicide ofthe germanosilicide layer and promote the growth of Pd(Si1-xGex).Concurrently, the smoothness of the germanosilicide layer was substantially improved in comparsion with those grown by vacuum annealingat temperature above 200℃. The studies also revealed that for a multiplepulse annealing at 0.1 J/cm2 with a low repetition rate, 1 Hz, the evolution of phase formation and Pd diffusion could be proceedeed by each individuallaser pulse.