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A hybrid Monte Carlo method was used to model the bulk transport properties of the AIxGa(1-x)N system, including degenerate statistics. Degeneracy was found to affect electron transport in both low and high field areas, and degeneracy inclusion lead to a pronounced negative differential mobility. A self-consistent solution of the Schrodinger and Poisson equations at the heterointerface was achieved via the Rayleigh-Ritz method.

The current-voltage characteristics of strained In Al As/In GaAs on InP substrate High Electron Mobility Transistors (HEMT's) are determined by a model based on variational change control model. The calculations are performed using the polynomial fit of two-dimensional electron gas (2DEG) density. The calculation reveals that the Indium mole fraction in the HEMT'sis inversely proportional to the threshold voltage and directly proportional to the drain current.

An analysis of the microwave performance of gallium arsenide-on-silicon metal semiconductor field-effect transistors (MESFETs) with silicon buffer layers is presented. In particular, the doping concentration and radio frequency characteristics of the MESFETs are investigated. Results show that the quality of the silicon buffer layer and the high resistivity of the substrate influence the radio frequency performance of the MESFETs.

Accelerated life testing of a 2-8-GHz amplifier is conducted to develop dual failure distribution functions for monolithic microwave integrated circuits. The principle of multifunctional distribution is used to provide a demarcation between early failure associated with passive components and the main failure distribution of the entire circuit. The role of matching on-chip and off-chip components on the failure distribution functions is also studied.

Material and process factors necessary in the assembly of ceramic chip capacitors onto alumina thick film layers in terms of phase reflow are analyzed. A Taguchi fractional factorial array is used for inner array analysis while a full factorial array is used for the outer. Results show that material incompatibility do not affect performance reliability since leakage failures are caused by the capacitors themselves.

Two dimensional computer modeling of the heat conduction process in a gallium arsenide monolithic microwave integrated circuit was conducted to study the thermal characteristics of the semiconductor chip during operation. The numerical simulations, which focused on the chip's energy dissipation and ambient temperature changes, revealed the inadequacy of simple computations based on thermal resistance networks to describe the spread of heat in such devices.

The electrical quality of HfO2 dielectrics grown by thermal atomic layer deposition at 175 °C on n-type (201) β-Ga2O3 has been studied through capacitance- and current-voltage measurements on metal-oxide-semiconductor capacitors. These capacitors exhibited excellent electrical characteristics, including dual-sweep capacitance-voltage curves with low hysteresis and stretch-out and a frequency-stable dielectric constant of k ~14 when measured between 10 kHz and 1MHz. The C-V curves exhibited a uniform and repeatable +1.05V shift relative to the ideal case when swept from 3.5 to ~5V, yielding positively measured flatband (+2.15 V) and threshold (+1.05 V) voltages that may be useful for normally off n-channel Ga2O3 devices. Using the Terman method, an average interface trap density of 1.3 x 1011 cm-2eV-1 was obtained between 0.2 and 0.6 eV below the conduction band edge. The forward bias current-voltage characteristic was successfully fitted to the Fowler-Nordheim tunneling model at a field strength of 5MV/cm, allowing an extraction of a 1.3 eV conduction band offset between HfO2 and Ga2O3, which matches the value previously determined from x-ray photoelectron spectroscopy. However, a temperature dependence in the leakage current was observed. These results suggest that HfO2 is an appealing dielectric for Ga2O3 device applications. [ABSTRACT FROM AUTHOR]