Metal-semiconductor Contacts: (No 19 Electrical & Electronic Engineering Monographs)

In modern semiconductor technology, contacts between semiconducting devices and the metal conductors that connect them with the rest of the system are of fundamental importance. This book deals with the basic science of such contacts, and discusses the electrical properties that are relevant to semiconductor technology. The topics covered include the mechanism of formation of Schottky barriers, the current/voltage relationship, the capacitance of rectifying contacts, and practical methods of fabricating contacts. The practical implications are emphasized wherever relevant to device technology, though there is no treatment of devices themselves. The main difference between this second edition and the first, is the expanded treatment of the physics of Schottky-barrier formation, together with some refinements in the discussion of electrical characteristics and of the effect of deep levels. The work is designed to be of value to semiconductor technologists and at physicists engaged in research on semiconductor interfaces as well as postgraduate and third year students.

Table of Contents:
Part 1 Surfaces, interfaces and Schottky barriers: historical; preliminaries - some surface properties of solids; the formation of a Schottky barrier including the Schottky-Mott theory; generalized analysis of the Bardeen model including the flat-band barrier, p-type semiconductors; intimate contacts; image-force lowering of the barrier; methods of measurement of barrier heights including photoelectric and capacitance measurements and photoelectron emission spectroscopy; electronegativity and work function. Part 2 Experimental studies of metals on semiconductors: metals on silicon and germanium; metals on III-V semiconductors including gallium arsenide, indium phosphide; metals on other semiconductors; summary and conclusions. Part 3 Current-transport mechanisms: emission over the barrier including the diffusion theory, the thermionic-emission theory; tunnelling through the barrier; recombination in the depletion region; hole injection; reverse characteristics; transient effects; the effect of an interfacial layer; the "T0" effect; numerical analysis of current flow. Part 4 The capacitance of a Schottky barrier: the capacitance of an ideal diode under reverse bias; the effect of an insulating layer with interface states; non-uniform donor distribution; C-V methods of measuring dopant concentrations; the effect of deep traps; the capacitance under forward bias. Part 5 Practical contacts: methods of manufacture including point, evaporated and sputtered contacts; the effects of heat treatment; silicides; control of barrier heights; Ohmic contacts. Appendices: A - the depletion approximation; B - exact analysis of the electric field in a Schottky barrier; C - comparison of Schottky diodes and P-N junctions; D - the hole quasi-Fermi level; E - contacts to amorphous semiconductors. References. Index.