This thesis deals with the numerical solution of the Boltzmann transport equation using an expansion of the distribution function in spherical harmonics for the purpose of electronic device simulation. Both the mathematical and physical backgrounds are discussed, then the Boltzmann transport equation is projected onto spherical harmonics without posing unnecessary restrictions on the energy ban...

We present a new Control Volume Finite Element Method (CVFEM) for the drift-diffusion equations. The method combines a conservative formulation of the current continuity equations with a novel definition of an exponentially fitted elemental current density. An edge element representation of the nodal CVFEM current density in the diffusive limit motivates this definition. We prove that in the ab...

The finite volume method is a popular method for the solution of systems of partial differential equations whenever local conservation properties are desired. However, engineering software usually does not reflect the underlying continuous mathematical formulation internally, but instead implements the discrete system directly, sacrificing a higher-level representation. As a consequence, the di...

This is a report of a survey on the incidence of carcinogenic activity in extracts of various kinds of human livers. It is based on extracts from 67 cases tested in 896 mice. Carcinogenic activity in extracts of human liver has now been reported by Schabad (11); Kleinenberg, Neufach, and Schabad (7, 8); des Ligneris (4); Hieger (6); Steiner (13, 15); and Sanni~, Truhaut, and Gu&in (10); and has...

iii ACKNOWLEDGEMENTS I would first like to thank my advisor Dr. Stephen Long for the opportunity to study here at UCSB. The graduate circuits courses he offered provided me with valuable foundation much needed to pursue this work. Special thanks goes to Hugh Finlay and Dr. Ken Weller at Skyworks Solutions for their support, encouragement, and technical advice. Thanks goes to my friends and coll...

In this thesis, models are presented for the design and analysis of carbon nanotube field-effect transistors (CNFETs). Such transistors are being seriously considered for applications in the emerging field of nanotechnology. Because of the small size of these devices, and the nearone-dimensional nature of charge transport within them, CNFET modeling demands a rigorous quantum-mechanical basis. ...

SiGe heterojunction bipolar transistors (HBTs) have been fabricated using selective epitaxy for the Si collector, followed in the same growth step by nonselective epitaxy for the p SiGe base and n-Si emitter cap. DC electrical characteristics are compared with cross-section TEM images to identify the mechanisms and origins of leakage currents associated with the epitaxy in two different types o...

Band gap narrowing is one of the crucial heavy-doping effects to be considered for bipolar devices. In case of HBTs, where discontinuities in the energy levels appear, the correct modeling of the energy barriers has basic importance for studying the device performance. Using the physically-based approach from [1], we present a new band gap narrowing model which considers the semiconductor mater...

This work compares NPN and PNP SiGe HBTs fabricated simultaneously using Ge' implantation in the base to achieve an average Ge concentration of 4at.%. Electrical measurements are presented and discussed with TEM and SIMS analysis. The results show that the PNP HBTs give superior performance to the NPNs, as they have more ideal collector characteristics. The NPN HBTs exhibit collector-emitter le...

Communication systems today comprise the major use of GaAs technology with the highest volumes found in the cellular handset front-end. Here, heterojunction bipolar transistor (HBT) power amplifiers (PA) and Pseudomorphic High Electron Mobility Transistor (PHEMT) switches enjoy a comfortable market share. In this environment, the demands of production design require a robust CAD system with acc...