In this work, we studied the possibility of synthesizing nanocrystalline germanium (Ge) via dry and wet oxidation of both amorphous and polycrystalline Si₀.₅₄Ge₀.₄₆ films. In dry oxidation, Ge was rejected from the growing SiO₂ forming a Ge-rich polycrystalline layer. As for wet oxidation, Ge was incorporated into the oxide, forming a layer of mixed oxide, SixGe₁₋xOy. Formation of nanocrystalline Ge was observed when the layer of SixGe₁₋xOy was annealed in a N₂ ambient. We have fabricated a metal-insulator-semiconductor structure with nanocrystalline Ge embedded within the insulator layer to study its feasibility as a memory device. / Singapore-MIT Alliance (SMA)

Thesis (M.E.E.)--University of Delaware, 2006. / Principal faculty advisor: James Kolodzey, Dept. of Electrical and Computer Engineering. Includes bibliographical references.

Thesis (Ph. D.)--University of Texas at Austin, 2001. / Vita. Includes bibliographical references. Available also from UMI/Dissertation Abstracts International.

Thesis (Ph. D.)--University of Texas at Austin, 2000. / Vita. Includes bibliographical references (leaves 178-187). Available also in a digital version from Dissertation Abstracts.

Thesis (Ph. D.)--University of Texas at Austin, 2003. / Vita. Includes bibliographical references. Available also from UMI Company.

No description available.

No description available.

Thesis (Ph. D.)--University of Texas at Austin, 2007. / Vita. Includes bibliographical references.

Active electronically scanned array (AESA) radar systems for military and commercial applications have fueled interest in low-cost, high-performance technologies capable of delivering integrated circuits for transmit-receive (T/R) modules and monolithic radar systems. Silicon-Germanium (SiGe) Heterojunction Bipolar Transistor (HBT) technology has been flagged as a strong candidate for such applications because of its high-speed low-noise devices, high integration capabilities, and relatively low cost. This work investigates integration issues associated with monolithic silicon-germanium radar systems for military (8-12 GHz) and automotive (24 GHz) applications. The design and implementation of critical circuits, such as phase shifters, power amplifiers, up-conversion mixers, down-conversion mixers, and voltage-controlled oscillators will be investigated, along with the system level considerations associated with these components. These building blocks have been fabricated and tested at wafer level, utilizing commercially available SiGe HBT BiCMOS technologies, demonstrating acceptable performance for these applications. Preliminary research into substrate coupling associated with these BiCMOS technologies will also be presented, demonstrating the potential for circuit-to-circuit substrate coupling to occur at these microwave frequencies.

The objective of this work was to design high-speed circuits using silicon-germanium (SiGe) heterojunction bipolar transistors (HBTs) and complementary SiGe (C-SiGe) HBTs, as well as silicon (Si) complementary metal oxide semiconductor (CMOS) devices, for next-generation ultra-wideband (UWB) transceivers. The advantages of using UWB systems over conventional narrowband transceivers include their lower power requirements, higher data rate, more efficient spectrum usage, precise positioning capability, lower complexity, and lower cost. The two major components in a UWB transceiver IC are the radio frequency (RF) circuit and the analog-to-digital converter (ADC). In this work, circuit-level solutions to improve the speed and performance of critical building blocks in both the RF front-end and the ADC are presented. Device-related issues affecting SiGe HBTs for potential applications in UWB systems intended for use in extreme environments will also be investigated. This research envisions to realize various circuit blocks in a UWB transceiver including, a 3-10 GHz UWB low noise amplifiers (LNAs) in both the second (120 GHz) and third (200 GHz) SiGe technologies, an 8-bit 12 GSample/sec SiGe BiCMOS track-and-hold amplifier (THA), and a fifth order elliptic gm-c low-pass filter in C-SiGe HBT technology. This research will also focus on characterizing SiGe HBTs for UWB electronics for operation in extreme environments by investigating the proton radiation effects in the third generation SiGe HBTs.