Approved for public release, distribution is unlimited / In this thesis, SiN films grown on Si substrates were characterized using Fourier Transform Infrared (FTIR) spectroscopy. The stress in SiN films can be used to enhance of mobility of electrons and holes which increases the performance of metal-oxide-semiconductor (MOS) transistors. The samples used in this study were prepared by Applied Materials using chemical vapor deposition (CVD) technique with different growth parameters. The stress of the samples varied from 1.3 GPa compressive to 1 GPa tensile depending on the growth conditions employed. The FTIR measurement showed three distinct absorption peaks associated with Si-N, Si-H and N-H vibrational modes. The hydrogen was unintentionally incorporated into the SiN film during the CVD process due to its use as the carrier gas for the precursors. It was found from the FTIR data that the area under Si-H and N-H peaks (amount of bonds) varies in opposite directions when the film stress changes from compressive to tensile. In addition, the peak position of the Si-H absorption shifted to higher energy while the opposite was true for N-H as the stress changes from compressive to tensile. The strength and the position of the Si-N absorption peak were found to be relatively insensitive to the stress of the film. This indicates that the amount of Si-H and N-H bonds in the film is responsible for controlling the stress of the film. The use of quantum calculation of SiN molecules with different amount of Si-H and N-H bonds was used toward understanding the experimental absorption spectra. / Lieutenant, Mexican Navy

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In this study, we discuss AlGaN/GaN high electron-mobility heterostructs grown by metal organic chemical vapor deposition technique. We analyzed the samples by optical and magnetoelectrical experiments to probe the dependence of the piezoelectric effect on the structural difference. We hope our results may be useful for the design of nitride heterostructures. The E-beam evaporator operation manual given in this thesis may be useful for future users.

Recent advances in wireless communication industry, radio- frequency circuits are developing fast. For power amplifiers, the active circuits are mainly composed of transistors where withstand high voltage and current. The excellent transistors characteristic result in good circuit performances. In the thesis, the modeling of InGaAs pseudomorphic high electron mobility transistor was provided by Win Semiconductor Corporation. The established small signal model contains extrinsic and intrinsic elements. The extrinsic elements are extracted by simple method without fitting process for long time. Then, the intrinsic elements are obtained by conventional matrix transformations. The each element of models is varied with different gate width area are also discussed. Finally, the nonlinear models are expanded upon the concept of small signal model. Due to some of intrinsic elements are significantly varied with bias, small signal models have not applied to nonlinear circuit simulations. For developing nonlinear models, the nonlinear elements characteristics are described by empirical fitting equations. The accuracy of models is achieved by comparing simulated and on wafer measurement results, including DC¡Bsmall signal and large signal power characteristics.

Thesis (M.S. in Applied Physics)--Naval Postgraduate School, December 2004. / Thesis advisor(s): Gamani Karunasiri, Ronald E. Brown. Includes bibliographical references (p. 33). Also available online.

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Current AlGaN/GaN Heterojunction Field Effect Transistors (HFETs) make use of multiple sources, drains, and gates in parallel to maximize transconductance and effective gain while minimizing the current density through each channel. To connect the sources to a common ground, current practice prescribes the fabrication of air bridges above the gates and drains. This practice has the advantage of a low dielectric constant and low parasitic capacitance, but it is at the expense of manufacturability and robust device operation. In the study described below, the air bridges in AlGaN/GaN HFETs were replaced by a polymer supported metallization bridge with the intention of improving ease of fabrication and reliability. The DC, high frequency, and power performance for several polymer step heights were investigated. The resultant structures were functional and robust; however, their electrical performance was degraded due to high source resistance. The cause of the high source resistance was found to be thinning of the metallization at the polymer step. The effect was more pronounced for higher step heights. / Master of Science

Cette thèse est une contribution à l'étude de composés semiconducteurs InX Al1-X N à forte teneur en Indium. Ces composés présentent des propriétés très intéressantes pour des applications dans le domaine de l'amplification des hyperfréquences. L'objectif principal de la thèse est de définir des hétéro-structures de type AlGaInN / GaN, pour transistors à Effet de Champ Piézoélectrique (HEMT), épitaxiées sur substrats de saphir, silicium, et SiC, optimisées en vue de l'amplification hyperfréquence. Dans la première partie, nous étudions la croissance épitaxiale de couches minces du composé binaire GaN, en phase vapeur, à partir de précurseurs organométalliques (MOVPE), dans des conditions optimisées pour obtenir des couches fortement résistives. La deuxième partie est consacrée à l'étude de structures HEMT AlGaN/GaN sur SiC et sur silicium. Sur SiC, nous montrons la forte influence des propriétés du substrat sur les propriétés électriques des structures HEMT. Nous avons étudié une structure nouvelle incluant une fine couche de AlN entre les couches AlGaN et GaN et évalué les performances de transistors HEMT AlGaN/GaN et AlGaN/AlN/GaN sur SiC et sur Silicium (111). La partie suivante est consacrée à la croissance de composés ternaires InAlN. Nous avons étudié l'influence de la température de croissance et du rapport V/III sur les propriétés structurales de InAlN. Les conditions optimales ont été utilisées pour la réalisation de structures HEMT InAlN/AlN/GaN. Nous démontrons l'influence considérable de la couche AlN sur les propriétés électriques de ces structures. Enfin, nous discutons les performances obtenues sur des transistors à effet de champ InAlN/AlN/GaN sur SiC / This work reports on the metal-organic vapor phase epitaxy and on the characterisation of III-N GaInAlN heterostructures for High Electron Mobility Transistors. In a first part, the heteroepitaxy of semiinsulating GaN layers on sapphire, SiC and silicon is presented as the basis for the subsequent growth of III-N HEMT structures. The influence of suitable nucleation layers on the properties of GaN is presented and discussed. A second part deals with AlGaN/GaN HEMT structures grown on SiC and on Si (111) wafers. The influence of SiC substrate properties on the electrical performances of AlGaN/GaN HEMT is presented. A novel structure, including a thin AlN interlayer between the GaN buffer layer and the AlGaN barrier layer has also been introduced. The section is completed by device results obtained on selected heterostructures. A study of the impact of selected growth parameter (i.e. growth temperature, V/III ratio) on the structural and surface properties of InAlN layers is then presented. The optimized conditions have been used for the growth InAlN/AlN/GaN HEMT structures which have been thoroughly characterized. The electrical properties of the structures were found to be strongly dependent on the growth conditions of the AlN interlayer (e.g. deposition time, V/III ratio). Finally, state of the art device results obtained with InAlN/AlN/GaN heterostructures are presented

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