Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 43 for “"Ohmic contact"”.
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Foundations of Ohmic Contact Formation on Aluminum Gallium Nitride/gallium Nitride Heterostructures
… and mm power amplifications. Fabrication of Ohmic contacts for such devices that meet the stringent low-resistance, high thermal stability and smooth surface morphology requirements has been challenging. In the cases where Ohmic behavior can be achieved, a full scientific understanding of the …
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A 12-bit 500 MHz GaAs MESFET digital-to-analog converter with p+ ohmic contact isolation
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1992.
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Monolithic Integration of Thermally Stable Enhancement-Mode and Depletion-Mode Indium Phosphide HEMTs Utilizing Iridium-Gate and Silver-Ohmic Contact Techniques
Excellent ohmic contacts based on Ge/Ag/Ni metallization have been developed for InAlAs/InGaAs/InP high electron mobility transistors (HEMTs) in a temperature range between 385 and 500°C for the first time. A minimum contact resistance of 0.06 O-mm was obtained at an annealing temperature of …
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Investigation of Ohmic Contacts for Gallium Nitride-Based Power Electronic Devices Using Molecular Beam Epitaxy
… and develop stable and reproducible low ohmic contacts through careful monitoring of the GaN surface and distribution of dopants while employing SAG by plasma assisted molecular beam epitaxy (PAMBE). The work specifically involved thin film growth, film characterization, device …
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Advanced Process Development for Contacts to Aluminum Gallium Nitride/gallium Nitride High Electron Mobility Transistors (Hemts)
… employing Ir/Pt/Au or Ni/Au gate and non-alloyed ohmic contact metallizations.
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Development of high-performance GaN-based power transistors
… epitaxy, a technology developed by our group for Ohmic contact improvement, is utilized to fabricate large-periphery AlGaN / GaN high electron mobility transistors (HEMTs) for high current operation. A novel Ti / Al multi-layered contact scheme is then introduced to further reduce the contact …
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Advanced process development for contacts to algan/gan high electron mobility transistors (HEMTS)
… stable than Ni/Pt/Au diodes. Ni/Au Schottky contacts exhibited good leakage response under thermal annealing for long periods. Microstructural studies were carried out on Ni/Pt/Au and Ni/Au Schottky contacts to elucidate the role of the intermediate layer, Pt, in the degradation of the …
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Analysis of Mo sidewall ohmic contacts to InGaAs fins
… a vertical nanowire field-effect-transistor, the Ohmic contact at the top of the nanowire not only covers the top surface, but also wraps around the sidewall. Because the sidewall is considered to be different from the top surface, it is necessary to study the sidewall Ohmic contact properties …
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A Critical Study of Gallium Nitride-Based Digital Technology
… adopted to minimize plasma-induced etch damage. Ohmic contact issues for n-GaN and p-GaN were also discussed. Finally, the test results of the preliminary BGJFETs were discussed with the future expectations and recommendations.
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Fabrication and characterization of AIGaN/GaN HEMTs
The processing procedure for the formation of ohmic contact using Ti/Al/Pd/Au, and Schottky contact using Pd/Au on AlGaN/GaN HEMT has been developed. A specific contact resistance of 1.08 x 10-7 W cm2 was achieved and an Schottky barrier height of 1.12eV was reached. Large dimension AlGaN/GaN HEMT …
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Home NILM : a comprehensive energy monitoring toolkit
… sensor can detect current and voltage with no ohmic contact to the wire. This enables power measurements from previously unavailable locations such as the front of the circuit breaker or the surface of a multi wire cable. This sensor is based off a Tunneling Magnetoresistive (TMR) element which …
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Sensing the human alpha rhythm using a non-contact electroencephalographic (EEG) electrode
… recorded using wet surface electrodes that make ohmic contact with the scalp surface using an electrolyte gel. Unfortunately, wet electrodes are intrusive to the user, problematic for EEG studies requiring high spatial resolution, and are unsuitable for long-duration EEG recordings. Wet …
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High-Performance Gateless Iii-Nitride Microwave Switches
… numerous applications. However, relatively high ohmic contact resistivity, large OFF-state capacitance, and difficulty in gate alignment limit HFET's application for RF switching to frequencies not exceeding 6 GHz. In this dissertation, a new type of gateless microwave switch using …
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Vertical gallium nitride power devices on bulk native substrates
… of the thesis studies the PiN diode. Low p-GaN ohmic contact resistance is obtained through annealing in oxygen ambient. The breakdown voltage reaches 1200 V with optimized field plate design. The resistance components of the PiN diodes are also analyzed in this part of the thesis. The second …
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Modelling of Multichannel GaN Transistors
… HEMT, this thesis compares the gate Schottky contact and ohmic contact, evaluating their reliability and the influence of the field plate on device performance. Further research extends to multichannel HEMTs, establishing a multichannel simulation platform to investigate the complexities of …
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A novel room temperature contacting technique applied to silicon solar cells
A novel room temperature technique for ohmic contact formation to silicon has been investigated for application in silicon solar cells. Point-contacting by Localised Dielectric Breakdown (PLDB) relies on localised high doping to ensure electric field based breakdown of a passivating dielectric …
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Development of InAlN HEMTs for space application
… process was optimised by adjusting the metal Ohmic contact formation process (specifically metal stack thicknesses and anneal conditions) and surface passivation techniques (plasma power during dielectric layer deposition), based on an existing AlGaN HEMT process. This resulted in both a …
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Atomic layer deposition Al2O3-passivated AlGaN/GaN high-electron-mobility transistors on Si(111) towards reliable high-speed electronics
… on foreign substrates, forming low-resistance ohmic contacts on (Al)GaN materials, properly passivating (Al)GaN surfaces, and reducing leakage currents are of great importance. In this dissertation, these challenges are individually addressed along with respective detailed studies. It is shown …
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Single particle spectrum of the two dimensional electron gas
… tunneling have been hampered by problems such as ohmic heating and low in-plane conductivity, while optical approaches probe long-wavelength excitations which can be difficult to interpret. Here we present a refined spectroscopic technique, time domain capacitance spectroscopy (TDCS), with which …
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Electronic devices based on semiconducting transition metal dichalcogenides
… extracted from back gate transistors, where the contact resistance is excluded with 4-point measurement for MoS2, and the histogram of mobilities is summarized for WSe2. Three different device structures based on exfoliated few-layer MoTe2 are proposed and fabricated: back gate transistor, …
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