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Showing 1 to 20 of 232 for “"gallium nitride"”.
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Foundations of Ohmic Contact Formation on Aluminum Gallium Nitride/gallium Nitride Heterostructures
Aluminum gallium nitride (AlGaN)/gallium nitride (GaN) high electron mobility transistors (HEMTs) have tremendous potential for application in high frequencies, high temperatures and microwave and mm power amplifications. Fabrication of Ohmic contacts for such devices that meet the stringent …
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Gallium Nitride Remote Epitaxy
… periodic polar bonds. The remote epitaxy of gallium nitride (GaN) is studied in depth. Freestanding GaN thin film with a threading dislocation density of 2.1×10⁷ cm⁻² and electron mobility of 254 cm²/(V·s) is demonstrated. The thin film is then transferred onto a host substrate and the original …
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Gallium nitride MEMS resonators
… breakdown fields and saturation velocities, Gallium Nitride (GaN) has been increasingly used in high-power, high-frequency electronics and monolithic microwave integrated circuits (MMICs). At the same time, GaN also has excellent electromechanical properties, such as high acoustic velocities …
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Advanced Processing Techniques for Aluminum Gallium Nitride/gallium Nitride High Electron Mobility Transistors
Using all the processing advancements demonstrated through the research undertaken in this dissertation highlights the potential of GaN-based transistors for next generation millimeter-wave applications, and possibly digital applications.
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Gallium Nitride phononic crystal resonator
We present a Gallium Nitride (GaN) Lamb Wave resonator using a Phononic Crystal (PnC) to selectively confine elastic vibrations with wide-band spurious mode suppression. A unique feature of the design demonstrated here is a folded PnC structure to relax energy confinement in the non-resonant …
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Ohmic Metallizations to Aluminum Gallium Nitride/gallium Nitride High Electron Mobility Transistors: Electrical and Microstructural Studies
"Major findings of this work include: (1) Elucidated the interfacial reactions between Al, Ti, AlTi alloy, and Ti/Al/Mo/Au on GaN. (2) Explained the electrical performance of Ti/Al/Mo/Au on AlGaN/GaN based on microstructural investigations. Proposed a ""spike"" mechanism. (3) Identified the role of …
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Aluminum Gallium Nitride/gallium Nitride HEMTs for High-Power Applications: Transistor Design Issues and Process Development
In this work, the development of fabrication process and transistor designs for high-performance AlGaN/GaN HEMTS required for high-power applications are presented. Three transistor designs under study are a gate-recessed HEMT, asymmetric HEMT with varying gate-drain spacing, and field-plate HEMT. …
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Advanced Process Development for Contacts to Aluminum Gallium Nitride/gallium Nitride High Electron Mobility Transistors (Hemts)
The developed ion-implantation process was used to propose fabrication schemes for novel high speed self-aligned and non-self-aligned AlGaN/GaN high electron mobility trasistors (HEMTs) employing Ir/Pt/Au or Ni/Au gate and non-alloyed ohmic contact metallizations.
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Controlled Lasing in Gallium Nitride Nanowires
… different material systems, including III-V, III-nitride, and II-VI semiconductors. However, due to the limited lasing control techniques, most of the nanowire lasers operate in naturally-occurring multi-mode and randomly polarized states. Lasing control in nanowire lasers is strongly desired for …
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CHARACTERIZATION OF DOPED GALLIUM NITRIDE SUBSTRATES
… of five bulk semi-insulated doped gallium nitride samples provided by Kyma Technologies, Inc were explored. The five GaN samples were grown on sapphire substrates by hydride vapor phase epitaxy (HVPE) and doped with different concentrations of iron, hydrogen, carbon, oxygen and …
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Gallium nitride nanowire growth and characterization
Includes bibliographical references (pages 109-117).
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Photoelectrochemical Wet Etching of Gallium Nitride
In this work, the technique of photoelectrochemical wet etching using KOH solutions has been developed for n-type GaN materials. Customized hardware and software have been assembled to carry out the etching. The etching characteristics were characterized over a wide range of process conditions. …
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Electronic properties of gallium nitride nanowires
This thesis presents a systematic study of the electrical transport in GaN nanowires. Particularly, the effect of the surrounding dielectric on the conductivity of GaN nanowires is experimentally shown for the first time. Our GaN nanowires are grown by catalytic vapor growth methods, specifically …
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Development of gallium nitride power transistors
GaN-based high-voltage transistors have outstanding properties for the development of ultra-high efficiency and compact power electronics. This thesis describes a new process technology for the fabrication of GaN power devices optimized for their use in efficient power distribution systems in …
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Junction Based Gallium Nitride Power Devices
… already reached the silicon's material limit. Gallium nitride (GaN) is a wide bandgap semiconductor with high electron mobility and high critical electric field. GaN-based power devices promise superior device performance over the Si-based counterpart. The primary design target of a unipolar …
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Multi-Kilovolt Gallium Nitride Power Transistors
… materials including silicon carbide (SiC) and gallium nitride (GaN). Benefitting from the wide bandgap, high electron mobility and good thermal conductivity of GaN, GaN-based power devices can achieve fast switching speed, high breakdown voltage, and small on-resistance. They have been deployed …
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Robustness of Gallium Nitride Power Devices
… This dissertation work studies the robustness of Gallium Nitride (GaN) power device. The structures of many GaN power devices are fundamentally different from Si or Silicon Carbide (SiC) power devices, leading to numerous open questions on GaN power device robustness. Based on the device …
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Metal-aluminium gallium nitride Schottky contacts formation.
X-ray photoelectron spectroscopy (XPS) has been used to investigate the effect of various surface cleaning procedures on Al[x]Ga[1]-[x]N surfaces for x = 0.20 and 0.30. Results show that wet chemical etch in a HF solution followed by a 600°C in-situ annealing under ultra-high vacuum (UHV) is …
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