Although there is a good deal of research concerning semiconductor impurities available, most publications on the subject are very specialized and very theoretical. Until now, the field lacked a text that described the current experimental data, applications, and theory concerning impurities in semiconductor physics. Impurities in Semicondu

This is the first book to describe thoroughly the many facets of doping in compound semiconductors. Equal emphasis is given to the fundamental materials physics and to the technological aspects of doping. The author describes various doping techniques, including doping during epitaxial growth, doping by implantation, and doping by diffusion. The key characteristics of all dopants that have been employed in III-V semiconductors are discussed. In addition, general characteristics of dopants are analyzed, including the electrical activity, saturation, amphotericity, autocompensation, and maximum attainable dopant concentration. Redistribution effects are important in semiconductor microstructures. Linear and non-linear diffusion, different microscopic diffusion mechanisms, surface segregation, surface drift, surface migration, impurity-induced disordering, and the respective physical driving mechanisms are illustrated. Topics related to basic impurity theory include the hydrogenic model for shallow impurities, linear screening, density of states, classical and quantum statistics, the law of mass action, as well as many analytic approximations for the Fermi-Dirac integral for three-, two- and one dimensional systems. The timely topic of highly doped semiconductors, including band tails, impurity bands, bandgap renormalization, the Mott transition, and the Burstein-Moss shift, is discussed as well. Doping is essential in many semiconductor heterostructures including high-mobility selectively doped heterostructures, quantum well and quantum barrier structures, doping superlattice structures and d-doping structures. Technologically important deep levels are summarized, including Fe, Cr, and the DX-center, the EL2 defect, and rare-earth impurities. The properties of deep levels are presented phenomenologically, including emission, capture, Shockley-Read recombination, the Poole-Frenkel effect, lattice relaxation, and other effects. The final chapter is dedicated to the experimental characterization of impurities. This book will be of interest to graduate students, researchers and development engineers in the fields of electrical engineering, materials science, physics, and chemistry working on semiconductors. The book may also be used as a text for graduate courses in electrical engineering and materials science.

This book discusses the theory of the electron states of transition metal impurities in semiconductors in connection with the general theory of isoelectronic impurities. It contains brief descriptions of the experimental data available for transition metal impurities belonging to iron, palladium and platinum groups and for rare-earth impurities in elemental semiconductors (III-IV, II-VI and IV-VI compounds) and in several oxide compounds (TiO2, BaTiO3, SrTiO3). Also included are applications of the theory to the optical, electrical and resonance properties of semiconductors doped by the transition metal impurities.The book presents a theory unifying previously proposed ligand-field and band descriptions of transition metal impurities. It describes the theory in the context of the general theory of neutral impurities in semiconductors and demonstrates the capabilities of this description to explain the basic experimental properties of semiconductors doped by transition metal impurities. A detailed discussion of various experimental results and their theoretical interpretation is carried out.This book comprises three parts. The first two parts consider several exactly solvable models and describe numerical techniques. All the models and simulations constitute a general pattern describing transition metal and rare-earth impurities in semiconductors. The final part uses this theory in order to address various experimentally observed properties of these systems.

This book emphasizes the importance of the fascinating atomistic insights into the defects and the impurities as well as the dynamic behaviors in silicon materials, which have become more directly accessible over the past 20 years. Such progress has been made possible by newly developed experimental methods, first principle theories, and computer simulation techniques. The book is aimed at young researchers, scientists, and technicians in related industries. The main purposes are to provide readers with 1) the basic physics behind defects in silicon materials, 2) the atomistic modeling as well as the characterization techniques related to defects and impurities in silicon materials, and 3) an overview of the wide range of the research fields involved.

First-generation semiconductors could not be properly termed "doped- they were simply very impure. Uncontrolled impurities hindered the discovery of physical laws, baffling researchers and evoking pessimism and derision in advocates of the burgeoning "pure" physical disciplines. The eventual banish ment of the "dirt" heralded a new era in semiconductor physics, an era that had "purity" as its motto. It was this era that yielded the successes of the 1950s and brought about a new technology of "semiconductor electronics". Experiments with pure crystals provided a powerful stimulus to the develop ment of semiconductor theory. New methods and theories were developed and tested: the effective-mass method for complex bands, the theory of impurity states, and the theory of kinetic phenomena. These developments constitute what is now known as semiconductor phys ics. In the last fifteen years, however, there has been a noticeable shift towards impure semiconductors - a shift which came about because it is precisely the impurities that are essential to a number of major semiconductor devices. Technology needs impure semiconductors, which unlike the first-generation items, are termed "doped" rather than "impure" to indicate that the impurity levels can now be controlled to a certain extent.

Recently, there has been a considerable upsurge of interest in heavily doped semiconductors. This interest is due primarily to the expanding range of applications of such. materials. Moreover, the heavy doping of semiconductors produces new effects (the forma tion of impurity aggregates, the appearance of allowed states in the forbidden band, etc J, which are of great interest in solid-state physics. The rapid growth in the number of papers on heavily doped semiconductors makes it difficult to review the results obtained so far. Therefore, many investigations carried out in 1966-7, par ticularly those on AIIIBV semiconductors, are not discussed in the present monograph, which represents the state of the knowledge in 1965. Nevertheless, the author hopes that, in spite of this, the book will be useful. An attempt is made, first, to review investigations of heavily doped semiconductors from a certain viewpoint and, sec ondly, to suggest some ideas (Chap. 5) which may be controversial but which are intended to stimulate further studies of heavily doped semiconductors which can be regarded as a special case of dis ordered systems. The work of American scientists investigating heavily doped semiconductors, in particular the efforts of E. O. Kane, J. 1. Pan kove, R. N. Hall, R. A. Logan, W. G. Spitzer, F. A. Trumbore, and many others, is well known to Soviet investigators. It gives me pleasure to learn that Western readers will now have an - v vi PREFACE portunity to become acquainted with the work done in the USSR.

A discussion of the different mechanisms responsible for contamination together with a survey of their impact on device performance. The author examines the specific properties of main and rare impurities in silicon, as well as the detection methods and requirements in modern technology. Finally, impurity gettering is studied along with modern techniques to determine gettering efficiency. Throughout all of these subjects, the book presents only reliable and up-to-date data so as to provide a thorough review of recent scientific investigations.