Electrical Characterization of GaAs Materials and Devices

The purpose of this book is twofold: (1) to summarize the present electrical-measurement data in GaAs materials and devices; and (2) to describe in detail the techniques used to obtain these data, including in most cases the theoretical basis of these techniques. It is this latter emphasis which is perhaps somewhat unusual in a work of this type, but which is, the author believes, essential for the understanding of the presented data, and moreover, for the ability of others to enter the field and contribute. In a sense, then, the present book is a cross between a reference work and a textbook, and, in fact, could be well used for a one-semester course on the electrical characterization of semiconductors, or as a strong supplementary text for a course on semiconductor physics. Many of the derivations are detailed, but the longer ones are relegated to appendices, in order to make the text more readable for those not interested in the mathematics. The choice of topics to cover, which is always difficult, has been made on the basis of what has been most useful in our own research. Special emphasis is given to subjects which are sometimes neglected in other works, such as impurity and defect Fermi functions, degeneracy factors, and multiband conduction, and also to subjects which are relatively new, such as the application of magnetoresistance to determine carrier mobility in device structures. Some of the information is very practical, e.g. how to make ohmic contacts, or where to buy a commercial, automated Hall-effect apparatus. Of course, it has also been necessary to leave out some topics which are relevant but which may have a limited application, such as the a.c. Hall effect and the de Haas-Shubnikov effect. It is hoped that the material will be useful to a majority of workers in the field.

Table of Contents:
Part 1 The hall effect and magnetoresistance: practical considerations; conductivity and hall coefficient; scattering theory - mobility; semiconductor statistics - carrier concentration. Part 2 Magnetoresistance in ungated structures - contact resistance patterns and gunn diodes: one-layer TLM and magneto-TLM analysis; two-layer TLM and magneto-TLM analysis; gunn diodes, and geometry corrections. Part 3 Capacitance and magnetoresistance in gated structures - field-effect transistors: gated capacitance - concentration profiling in MESFETs; gated capacitance and conductance - mobility profiling in MESFETs; gated magnetoresistance - mobility profiling in MESFETs; gate current and parasitic-resistance effects; capacitance and magnetoresistance in MODETs. Part 4 Capacitance and conductance effects from deep traps: steady-state effects; transient behaviour - emission and capture; temperature spectrosocpy - DLTS; optical excitation in ungated structures - PICTS and HETS. Appendices: solutions to differential equations; multi-band conduction; semiconductor statistics; commercial hall effect instruments.