Dissertations / Theses on the topic 'Thick films. Thick-film circuits'

Methods of noise coupling in high speed thick film circuits has been investigated. Parasitic coupling parameters have been experimentally determined for a variety of single and multilayer thick film layouts. In addition, the severity of the problem has been studied by measuring coupled noise induced on carefully constructed test cards. Curves are presented as an aid for predicting noise levels as a function of conductor spacing and signal edge speed. The measurements are discussed quantitatively and guidelines for the design of high speed thick film circuits are summarized.

This dissertation presents methods for wideband characterization and modeling of magnetic materials and structures over a wide frequency range (dc to a few GHz). A method for modeling the thick film inductor structures at high frequencies is presented in this dissertation. The thick film inductor under test is printed and located in shunt connection at the end of a reference transmission line. Time Domain Reflectometry (TDR) technique is used to measure the response waveform from the inductor under test. The response from a short circuit at the location of the inductor is acquired as the reference waveform. The two acquired waveforms are then transformed into the frequency domain using the Fast Fourier Transform algorithm (FFT). The reflection coefficient is then computed as the ratio between the Fourier Transforms of the response and reference waveforms. From the information contained, the complex impedance of the structure under study can be calculated. This information is used for modeling that structure by fitting the data to the network model using the computer network analysis program. Experimental and simulated response waveforms are compared and brought to a close match by changing the model components values. A cavity-like sample holder filled with ferrite material ls proposed in this dissertation to measure the complex permeability of the magnetic material filling this cavity. The cavity walls are deposited on a coaxially shaped sample using thick film techniques. The reflection coefficient from the cavity under study is measured by adapting the cavity to the end of a transmission line. The full field analysis of this proposed configuration is used to determine a relationship between the complex permeability of the ferrite material and the measured reflection coefficient. The method of moments ls used to achieve this task. Computer simulation experiments are performed to test the sensitivity of the technique and to predict the performance over the desired frequency range. Actual experimentation as well as verifications of these measurements are conducted to verify the merit of the proposed technique.
Ph. D.
incomplete_metadata

Master of Science
Department of Electrical Engineering
William B. Kuhn
Designers of mixed-signal systems must understand coupling mechanisms at the system, PC board, package and integrated circuit levels to control crosstalk, and thereby minimize degradation of system performance. This research examines coupling mechanisms in a RF-targeted high-resistivity partially-depleted Silicon-on-Insulator (SOI) IC process and applying similar coupling mitigation strategies from higher levels of design, proposes techniques to reduce coupling between sub-circuits on-chip. A series of test structures was fabricated with the goal of understanding and reducing the electric and magnetic field coupling at frequencies up to C-Band. Electric field coupling through the active-layer and substrate of the SOI wafer is compared for a variety of isolation methods including use of deep-trench surrounds, blocking channel-stopper implant, blocking metal-fill layers and using substrate contact guard-rings. Magnetic coupling is examined for on-chip inductors utilizing counter-winding techniques, using metal shields above noisy circuits, and through the relationship between separation and the coupling coefficient. Finally, coupling between bond pads employing the most effective electric field isolation strategies is examined. Lumped element circuit models are developed to show how different coupling mitigation strategies perform. Major conclusions relative to substrate coupling are 1) substrates with resistivity 1 kΩ·cm or greater act largely as a high-K insulators at sufficiently high frequency, 2) compared to capacitive coupling paths through the substrate, coupling through metal-fill has little effect and 3) the use of substrate contact guard-rings in multi-ground domain designs can result in significant coupling between domains if proper isolation strategies such as the use of deep-trench surrounds are not employed. The electric field coupling, in general, is strongly dependent on the impedance of the active-layer and frequency, with isolation exceeding 80 dB below 100 MHz and relatively high coupling values of 40 dB or more at upper S-band frequencies, depending on the geometries and mitigation strategy used. Magnetic coupling was found to be a strong function of circuit separation and the height of metal shields above the circuits. Finally, bond pads utilizing substrate contact guard-rings resulted in the highest degree of isolation and the lowest pad load capacitance of the methods tested.

The master thesis deals with multilayer structures and thick film technology. The main goal of this work is measure basic electric features of structures realized with thick film technology. The results will make possible more accurate design of these structures.

La tecnologia thick film pot definir-se com el procés on es du a terme la creació de dipòsits de circuits impresos en un substrat de ceràmica rígida mitjançant la tècnica de la serigrafia. Les pastes que s’utilitzen per aquest propòsit es formulen amb l’addició de vidres i diferents òxids que promouen l’adhesió dels dipòsits generats al substrat a temperatures entre 600 i 950ºC. Per altra banda, la tecnologia ceràmica multicapa, permet una disposició densa de circuits impresos incorporant components interns en un únic dispositiu amb estructura multicapa monolítica. Els substrats ceràmics pels sistemes multicapa presenten una baixa constant dielèctrica similar als substrats tradicionals emprats en la tecnologia thick film i les pastes per dur a terme les metal•litzacions s’ha de dissenyar per tal de co-sinteritzar amb el substrat ceràmic. La primera mostra d’aquesta tecnologia la trobem en els sistemes HTCC (High Temperature Co-fired Ceramics) que es basen tradicionalment en l’ús de materials basats en alúmina. L’elevada temperatura de cocció que requereixen aquests substrats (aprox. 1600ºC) limita el nombre de materials conductors amb els quals poden co-sinteritzar. Aquests conductors solen ser tals com el W, Mo, Mn i Pt. L’evolució d’aquesta tecnologia la trobem en l’ús de compostos vitro ceràmics que cristal•litzen i reaccionen total o parcialment amb diferents òxids addicionats a la mescla de vidres. L’ús de vidres de baix punt de fusió que envolten els additius ceràmics és una altra aproximació a aquesta evolució de la tecnologia. Es tracta del que s’ha anomenat LTCC (Low Temperature Co-fired Ceramics) i que permet unes temperatures de sinterització per sota dels 950ºC fent viable l’ús de materials d’elevada conductivitat (Ag, Au, Cu...) que co-sinteritzen amb el substrat. Tant la tecnologia thick film com la tecnologia ceràmica multicapa són el nexe que uneix tots els estudis que s’han realitzat en aquest treball. Els camps sobre els quals ha girat l’aplicació d’aquesta tecnologia són per una banda, els sensors d’oxigen dels gasos d’escapament del vehicle (exhaust gas oxygen sensors), concretament els basats en un òxid semiconductor, el diòxid de titani, per ser usat com a sonda lambda i per altra banda, els sensors ceràmics capacitius i la viabilitat de fabricar-los amb materials LTCC. La primera part del treball és una introducció a les tecnologies emprades, les característiques de les quals en ajudaran a entendre certs detalls en l’evolució d’aquest estudi que es relacionen íntimament amb el tipus de tecnologia utilitzada. Pel que fa el sensor lambda basat en diòxid de titani, la primera part de l’estudi ha consistit en la preparació d’un material catalític amb una elevada àrea superficial dispersat en el suport porós de TiO2. El procediment ha consistit en realitzar mètodes d’impregnació i l’objectiu ha estat establir els principals paràmetres que afecten al procés d’addició del catalític i determinar la mínima quantitat de material necessària per tal d’obtenir un dispositiu sensor basat en Pt-TiO2 adequat per ser usat com sensor lambda. En aquesta primera part, el dipòsit del material sensor es realitzà amb tècniques thick film sobre un substrat d’alúmina HTCC ja sinteritzat. El següent pas pel que fa el sensor de TiO2 va ser l’estudi de la millora en el seu procés de fabricació centrant els esforços en aconseguir una millor adhesió entre el material sensor i el substrat d’alúmina. L’objectiu fou eliminar el major nombre de processos thick film després del sinteritzat del substrat (post-firing) amb diferents propostes per dipositar el material sensor sobre la ceràmica en verd i co-sinteritzar els dos elements. Els treballs van consistir en el disseny de pastes adequades per poder dipositar el material sensor, l’estudi del paper dels compostos de titanat d’alumini que es formen a la temperatura de sinterització de l’alúmina, la caracterització funcional dels dispositius proposats i finalment, com aquests mètodes proposats afecten a l’addició del material catalític. Els resultats obtinguts han permès establir una quantitat de platí del 1.8% en pes, respecte la quantitat de TiO2 en el dispositiu. Amb mètodes d’impregnació s’ha obtingut una pols de partida amb la qual s’ha preparat una pasta que aplicada amb tècniques thick film ha permès la obtenció de dispositius aptes per treballar com a sensor lambda. En quant a la co-sinterització del material sensor els millors resultats s’han obtingut controlant el grau de formació de titanat d’alumini i controlant la seva estabilitat tèrmica amb l’ús de l’MgO com additiu en la formulació de la pasta del material sensor. La porositat del material sensor juga un paper crucial en aquest mètode degut al fet que l’addició del material catalític s’ha dut a terme mitjançant processos post-firing per tal d’evitar les elevades temperatures de sinteritzat. Pel que fa els sensors de pressió ceràmics capacitius, el treball es focalitzà en l’estudi de la viabilitat dels materials LTCC per tal de fabricar aquest tipus de dispositius. Es van dur a terme comparacions entre les característiques funcionals de dispositius fabricats en tecnologia thick film sobre alúmina i dispositius amb membranes flectores de diferents materials LTCC i es caracteritzà la seva sensibilitat així com la seva estabilitat en la resposta. Finalment es proposà un dispositiu miniaturitzat plenament integrat en tecnologia LTCC en el qual es caracteritzà la seva resposta. Els resultats obtinguts avalen la possibilitat d’utilitzar els materials LTCC per fabricar sensors de pressió ceràmics capacitius. S’han establert els criteris de planitud i distància entre elèctrodes en funció de la mida de l’elèctrode de mesura del dispositiu. La caracterització funcional ha mostrat la dependència del disseny amb el tipus de fluid de pressió, la sensibilitat requerida i el rang de pressió de treball. La capacitat paràsita generada per la interacció entre el fluid incident i el dispositiu i les condicions de segellat són els aspectes principals que afecten a l’estabilitat de la resposta.
The thick film technology can be defined as the process that involves the deposition of metal circuitry on an already fired ceramic substrate using screen-printing technology. Pastes for this purpose are formulated with glass frit and oxides to promote the adhesion to the substrate firing the parts at low temperatures (600-950ºC). By the other hand, the multilayer technology allows a dense circuitry layout incorporating buried components in a single, monolithic, hermetic package. Ceramic substrates for the multilayer systems use low dielectric constant materials similar to traditional ceramic substrates for thick film technology and pastes for metallization that must be designed in order to co-fire with ceramic substrate. First approach of this technology was the high temperature co-fired ceramics (HTCC) traditionally based on alumina material. The relatively high temperature of alumina-based ceramics (approx. 1600ºC) limits the number of conductor materials able to co-fire with ceramic substrate. Such conductor materials are typically based on W, Mo, Mn and Pt. Next approach of this technology, involves the use of glass-ceramic based materials that undergo devitrification to a crystalline phase during firing or containing glass frit with low temperature melting point and different crystalline fillers. Development of Low Temperature Co-fired Ceramics (LTCC) allow to decrease the firing temperature down to 950ºC and conductor pastes based on high conductivity materials (Ag, Au, Cu…) can be used to co-fire with these substrates. Thick film and multilayer ceramic technology are both the link of the work carried out. The fields in which both technologies have been deployed are by one side, the heated exhaust gas oxygen sensor (HEGO), specifically semiconductor gas sensor based on TiO2 suitable to use as lambda probe and by the other side, the ceramic capacitive pressure sensors and its availability to be manufactured using LTCC materials. First part of the work is an introduction to the technologies and main features that will help us later to understand details on the work development, that are strongly influenced by the kind of technology we are working with. Regarding lambda sensor based on TiO2, first part of the study have consisted of a process for preparing a catalyst which has a high surface area, finely divided and catalytically active on a porous carrier structure based on titania. Process was based on impregnation methods and the aim of this work was to establish main parameters that affect deposition control and to determine minimum amount of catalyst which is needed in order to get suitable Pt-TiO2 based sensor to be used as lambda probe. In this approach sensor deposit is generated using thick film technologies over an alumina HTCC substrate. Next step regarding titania sensor was to study the improvement of manufacturing process in order to improve the adhesion between sensor material and alumina based substrate. This approach was focused in to avoid thick film post-firing processes proposing and single sensor material deposition in green state and co-firing both substrate and sensor material. The aim of this work was to design sensor pastes in order to get suitable sensor deposit, to study the role of aluminum titanate compounds generated at firing temperatures, to study the functional features of proposed devices and finally how this method affects the catalytic material addition. Results lead us to establish a minimum amount of 1.8wt% of Pt/TiO2-nominally using impregnation methods to obtain impregnated titania powder which can be applied to the substrate using thick film technology (prior paste preparation). Response of the devices is suitable to be used as lambda sensors. The sensor material co-firing approach gave us better results by controlling the amount of aluminum titanate formation and controlling its thermal stability by using MgO as additive in sensor material paste formulation. Porosity of the sensor material plays a key role in this approach due to the fact that catalyst addition must be done in post-firing process in order to avoid high sintering temperatures. Regarding ceramic capacitive pressure sensors, the work was focused in the study of suitability of LTCC as materials for manufacturing such devices. Comparison between functional features of thick film over alumina devices and LTCC membrane devices were carried out and sensibility and response stability was characterized as well. Finally, a miniaturized, fully integrated LTCC device was proposed and the sensor response was characterized. Results showed us the feasibility of LTCC materials to be used in capacitive pressure sensors. Flatness criteria was established regarding measuring electrode size and the functional characterization gave us as result the sensor design dependence on the kind of working fluid, accuracy and pressure range. Parasitic capacitance generated by device interaction with working fluid and sealing conditions was established as main features that can affect the stability in the response.

The aim of this master’s thesis is to investigate the electrical properties of various thick-film resistor pastes in a wider temperature range. The thesis mainly focuses on a change in electrical resistance depending on temperatures, which extend to the cryogenic region. To achieve this, there is an overview of the thick-film technology properties, major technological procedures, principles of resistive pastes conductivity, methods of electrical resistance measuring, possible errors in measurement and methods of their minimization. The content of this work is also familiar with the characteristics of a cryogenic station, on this foundation was proposed the measurement procedure and created thick-film circuits for this station. After measurement in the interval 10 K to 350 K, there are subsequently evaluated the data and explains the principles of the conductivity of used pastes.

Thesis (Ph. D.)--University of Delaware, 2004.
Principal faculty advisor: S. Ismat Shah, Robert L. Opila, Dept. of Materials Science & Engineering. Includes bibliographical references (leaves 171-178).

High Temperature Superconductors (HTS) materials are ideal for many electrical applications. These applications include high speed interconnects, microwave structures and transmission lines, as well as electronic devices that utilize the unique electrical and magnetic properties of these materials. To date, the use of high temperature superconductors has been limited to a narrow range of substrate materials, due to the reactive nature of these superconductors. Chemical reactions between the substrate and the superconductor cause decomposition of the superconductor into an insulator. The researcher has developed a thick film system that allows the production of high quality HTS films on reactive substrates, such as alumina (Al203). This system utilizes a thick film buffer layer of pure silver in combination with thick film superconductors composed of Y1Ba2~CU30X. The silver buffer layer is designed to prevent contact between the substrate and the superconductor, thereby eliminating chemical reactions between the two materials. The development as well as the comprehensive characterization of these films is described in this work.
Master of Science

Ceramic substrates play an important role in thick film hybrid microelectronic circuits. Existing substrates such as alumina and beryllia do not meet satisfactorily the desired requirements. The newly developed aluminum nitride (AIN) substrate shows a great deal of promise and potentially embraces the best qualities of alumina and beryllia. The objective of this dissertation is to study the electrical properties, thick film interaction, and environmental effects on AIN substrates, and also to examine the performance of this material for high power - high frequency hybrid thick film applications. In particular, wideband dielectric constant measurements of A1N and other ceramic substrates are performed, oxidization and humidity effects on surface properties of AIN are addressed, and short and long term aging effects on several circuit parameters are studied. To evaluate the performance of AIN in high power and high frequency applications, two circuits; an impulse generator and a power converter, are realized, tested and compared with those on alumina substrates. The thick film circuits realized on AIN perform considerably better than those on alumina.
Ph. D.

Abstract In gravure offset printing, ink is transferred with the help of an offset material from a patterned gravure plate to a substrate. This thesis is concerned with the study and further development of this printing process for electronics; on alumina, glass and polymers. The work has been divided into five parts. In the first section, the printing process is described. The second section describes the composition of the inks for gravure offset printing and the resulting ink properties. It also presents the ink transfer mechanism; the model that explains how the ink is transferred between an offset material and a substrate. The third chapter details the printing process explained by a solvent absorption mechanism. The forth chapter describes the firing/curing of printed samples and their properties. The last chapter describes applications of the method. The inks used to produce conductors on ceramics (ceramic inks) and conductors on polymers (polymer inks) contain silver particles, and were under development for gravure offset printing. The major achieved properties were the high ink pickup to the offset blanket and high transfer percentage to the substrate. 100% ink transfer from blanket to substrate for ceramic inks and almost 100% ink transfer for polymer inks was obtained. The printing of ceramic inks was able to produce 8 μm of relatively thick, 300 μm wide lines with < 10 mΩ/sq. resistance. The minimum line width for conducting lines was 35 μm, with one printing. Multi printing was applied producing as many as 10 times wet-on-wet multiprinted lines with 100 % ink transfer from blanket to substrate resulting in a square resistance of 1mΩ/sq. Polymer inks were able produce a square resistance of 20 mΩ/sq. for 300 μm wide lines after curing at 140 °C for about 15 min, and the minimum width was down to 70 μm. In the optimised manufacturing process, the delay time on the blanket was reduced to 3 s. In addition to ultra-fine-line manufacturing of conductors, the method enables the manufacture of special structures e.g. laser-solder contact pads with 28/28 μm lines/spaces resolution. With industrial printing equipment it is possible to produce 100 m2/h with the demonstrated printing properties.

A new family of dielectric materials has been studied, individually as thick-film capacitors and as buried components incorporated in second-order lowpass and bandpass RC active filter circuits. The materials were electrically characterized in terms of the variation of dielectric constant and dissipation factor with frequency. The performance of the filter circuit is related to the characteristics of the dielectric materials. An analysis of the circuit is developed which accounts for the capacitor losses.
Master of Science

Le circuit etudie est un preamplificateur d'impulsions rapides, dont un certain nombre (60) fait partie d'une chaine electronique associee a un detecteur a gaz xyzt. Cet ensemble permet d'effectuer des mesures de temps, de position et de pente d'energie dans le cadre des ions lourds a basse energie. Apres une realisation classique en circuits imprimes pour determiner les caracteristiques du circuit (gain, temps de montee, bruit, etc. ), on realise celui-ci en technologie hybride couche epaisse

This thesis deals with non-conventional applications in the area of thick film technology, especially with indication of the temperature by thermodynamic sensors. The work summarizes thermodynamic sensors theory and also contains production data of the universal thermodynamic sensor realized on ceramic substrate, including measurement of its parameters and heat radiation.

Cette étude a été motivée par les nombreux avantages du procédé de micromoulage, qui couple la croissance électrolytique et la localisation du film avec un moule en résine épaisse. Ce procédé permet en effet la réalisation de micro-objets, dont les dimensions sont uniquement dépendantes de la résolution des techniques de lithographie employées pour définir les moules en résine. Le micromoulage permet donc de réaliser des microstructures métalliques et est compatible avec la technologie MEMS. Nous avons mis en évidence l'influence de différents paramètres expérimentaux dans le cadre de l'étude de la croissance électrolytique du samarium-cobalt en solution aqueuse dans une cellule de Hull. Cette étude nous a permis de déterminer plusieurs points de fonctionnement conduisant à des teneurs en samarium et des épaisseurs élevées : jusqu'à 50 % de samarium et plusieurs microns d'épaisseur. En outre, un certain nombre d'hypothèse ont été émises, qui lient le procédé d'élaboration et le mécanisme de croissance. Nous avons aussi réussi a montré qu'il est possible de réaliser des micromotifs de plusieurs microns d'épaisseur contenant un rapport Sm/(Sm+Co) relativement élevé (10 %) et une faible contamination en oxygène (8 %).

Dans une etude theorique des structures a profil d'indice continu, il est montre que l'essentiel des proprietes spectrales des filtres a profil d'indice sinusoidal peut etre etudie de maniere analytique a partir de certaines proprietes de l'equation de mathieu. L'etude experimentale de ces structures a ete realisee a l'aide d'une technique de coevaporation par masquage mecanique. L'equipement de depot realisant la coevaporation a ete developpe pour permettre la realisation de couches sur substrat chaud pour des profils d'indice quelconques. Un systeme de mesure optique multispectral in-situ en reflectivite a egalement ete mis au point. Les proprietes des couches minces de melanges de znse et de laf3 ont ete etudiees pour toute la gamme de composition. Un schema d'evolution de la structure cristalline et de la porosite des couches en fonction de leur composition est propose. Les contraintes qui s'y developpent sont aussi analysees ainsi que leur evolution en fonction de l'environnement. L'etude des proprietes optiques a permis de definir les lois de melange ainsi que de mettre en evidence l'existence d'une birefringence evoluant avec la composition des melanges. Enfin, plusieurs types de structures periodiques ont ete realisees, comportant jusqu'a 20 periodes pour une epaisseur superieure a 5m. Les resultats ont permis de montrer que la modulation par masquage mecanique est une technique fiable et precise et que c'est le choix du couple de materiaux qui va conditionner la precision du controle du profil d'indice

碩士
國立高雄應用科技大學
電子與資訊工程研究所碩士班
95
In this thesis, we proposed an equivalent circuit model and measured various parameters of the alternating-current thick-film electro- luminescent device. Combined with the luminance-charge relation of the phosphor layer deduced by experiment and Sawyer-Tower circuit measurement, we can calculate and predict the voltage-luminance characteristics of the electroluminescent device with various dielectrics composition. Compared with the theoretical calculation and experimental result, the deviation is less than 20% and proves the validity of our proposed equivalent circuit model. Both theory and experimental results indicated that the luminance of the electroluminescent device is linear dependent with phosphor layer charges. However, phosphor layer charges do not proportional to the capacitance value of the dielectric layer. Charges will get saturation and induces the saturation of luminance of the device. For example, when we increases the capacitance of the dielectric layer to 10nF with a 2 cm × 2 cm sample, the phosphor layer charges will reach 90% of the saturation value. The luminance of the electro- luminescent device will be limited no matter what other dielectric materials and compositions are adopted. In order to improve the luminance efficiency and drift the color, we doped D-YAG powder into the phosphor layer. The D-YAG powder would absorb blue and blue-green light and emit green light. It makes the emitting light of the electroluminescent device moving to the sensitive area of human eyes and enhanced the luminance. When operated at 150V and 400Hz of alternating-current voltage, the CIE coordinate shifted from (0.16, 0.36) to (0.20, 0.43) and the luminance efficiency increased 10% for the electroluminescent device composed by GG24 phosphor and D-YAG powder. By mixing the GG64 phosphor and D-YAG powder, the CIE coordinate of the electroluminescent device changed from (0.158, 0.197) to (0.21, 0.29) and the luminance efficiency increased 20%.

碩士
華梵大學
機電工程研究所
90
The biosensors are very unfavorable in measurement because the working electrode will be polluted after detecting chemical solution. In order to avoid this problem, the disposable sensors must be developed in the future. The screen-printed carbon electrode can support the requirement because of its cheap price and mass production. Besides, if the screen-printed carbon electrode can be suitable to the extended gate ion sensitive field effect transistor measurement system which can not be affected by nature light and easily package, the low cost biosensors will be expected. In this thesis, first the pH value was measured by carbon electrode. We use two electrodes — carbon and Ag/AgCl to measure the response. The response of pH value was obtained and the sensitivity is between 30mV/pH and 45mV/pH. Next, we detect the urea concentration variation. We change the measurement structure to detect the urea concentration. The electrodes are three carbons and we employ differential pair structure of instrument amplifier to obtain the output voltage response. The linear range of urea is from 5mg/dl to 80mg/dl. The limitation of output voltage is about 93mV. This value is suitable to the pH value variation system. So we can prove that the carbon electrode detected urea concentration also can be used in the potentiometric circuit. At last we study the biosensor readout circuit. In the article, the readout circuit type will be conferred and we make use of the VLSI technology to fabricate its readout circuit chip. Then we hope the chip can match with the screen-printed carbon electrode.

碩士
國立交通大學
電子物理系所
96
In this work, we propose a new process to fabricate porous SiO2 as epitaxial lateral overgrowth (ELOG) mask. Nanometer or micrometer scale porous Ni film formed by the dewetting of two-dimensional Ni film on SiO2 during rapid thermal annealing was investigated. The hole size varied by different annealing conditions and the thickness of the Ni film. Then porous SiO2 was fabricated by using dewetted Ni film as an etching mask. GaN with a thickness of 150~200μm was grown by hydride vapor phase epitaxy (HVPE). The strain released near the interface of the GaN thick film and the sapphire substrate by this structure was investigated by cross-sectional micro-Raman analysis. The residue strain near the interface of the sample grown on the porous SiO2 template was less than that of which grown on the stripe patterned one. The dislocation density of 4.4x107/cm2 was estimated by the etching pit density.

碩士
國立臺灣科技大學
電子工程系
95
In this research,we discuss the Excimer Laser Crystallization of thick Si films, and we manufacture the Poly-Si Thin-Film Solar Cells by this film. In the research, we can find the crystallization by Excimer laser of 700nm Si film.And the complete melting characteristic is Disc grain. We can produce lateral growth length about 7um by SLS.Finally we use this film to manufacture P+ P N diode. n =3.37 , ON/OFF=20.