Dopants and Defects in Semiconductors

Matthew D. McCluskey, Eugene E. Haller

• Publisher: CRC Press
• Year: 2018
• ISBN:
  9781351977975
• Edition: 2
• Topic: Physical Sciences
• Subtopic: Condensed Matter

Praise for the First Edition

"The book goes beyond the usual textbook in that it provides more specific examples of real-world defect physics … an easy reading, broad introductory overview of the field"
? Materials Today

"… well written, with clear, lucid explanations …"
?Chemistry World

This revised edition provides the most complete, up-to-date coverage of the fundamental knowledge of semiconductors, including a new chapter that expands on the latest technology and applications of semiconductors. In addition to inclusion of additional chapter problems and worked examples, it provides more detail on solid-state lighting (LEDs and laser diodes). The authors have achieved a unified overview of dopants and defects, offering a solid foundation for experimental methods and the theory of defects in semiconductors.

Matthew D. McCluskey is a professor in the Department of Physics and Astronomy and Materials Science Program at Washington State University (WSU), Pullman, Washington. He received a Physics Ph.D. from the University of California (UC), Berkeley.

Eugene E. Haller is a professor emeritus at the University of California, Berkeley, and a member of the National Academy of Engineering. He received a Ph.D. in Solid State and Applied Physics from the University of Basel, Switzerland.

1

Semiconductor Basics

In this chapter, the fundamentals of semiconductor physics are presented. After a brief historical overview, we discuss examples of crystal structures that are relevant to semiconductors. We then discuss the most important properties of semiconductors: phonons, band structure, electronic transport, and optical properties. This is followed by a section on specific semiconductor materials.

1.1Historical Overview

In the early 1870s, Ferdinand Braun, a high school teacher in Leipzig, connected metal wires to natural semiconducting minerals such as galena (PbS). To his surprise, he found that the current flow was not proportional to the applied bias (Braun, 1875). Ohm’s law, so successful for metals, did not hold for these metal–mineral contacts. Braun’s discovery eventually led to the solid-state rectifier. Although the underlying physical principles were not understood, wireless telegraphy and radio engineers soon used “crystal detectors” for the demodulation of amplitude-modulated radio-frequency signals. Braun played a key role in the development of early radio science and technology and also invented the TV picture tube, which in German is called the Braunsche Röhre. He was awarded the Nobel prize in 1909 jointly with Guglielmo Marconi.

A variety of materials were used as rectifiers. PbS was used in crystal radios. Other early semiconductors used as crystal detectors and AC rectifiers included copper oxide (CuO), selenium, and pyrite (FeS). Because uncontrolled impurities and defects led to widely variable crystal properties, however, the crystal detectors were perceived as an unreliable technology. Some famous physicists expressed doubts regarding the very existence of semiconductors. They called the unpredictable phenomena the “physics of dirt.”

Starting in the 1920s, a more “modern” device, the vacuum tube, began permeating electronics and kept its dominant position until the 1960s. There was, however, one area of electronics where tubes could not perform. The urgent need for sensitive, ultra high frequency rectifiers for radar reception during World War II led to the development of silicon and germanium point contact rectifier diodes (Torrey and Whitmer, 1948; Seitz, 1995).

In addition to current rectification, semiconductors exhibited unusual temperature-dependent behavior. In contrast to metals, when a pure semiconductor is warmed up, its resistance drops. In semiconductors, electrons fill a band of energy states (Wilson, 1931), now called the valence band. Due to the Pauli exclusion principle, the electrons in these filled states could not respond to an electric field. Only electrons that were thermally excited into a higher band (the conduction band) could conduct electricity. Building on these insights, Walter Schottky developed a theory explaining rectification at metal-semiconductor junctions, over a half century after Braun’s discovery (Schottky, 1938).

Driven by the need for rectifiers in radar systems, researchers attempted to improve the quality of semiconductor materials. At Bell Labs, Russel Ohl and Jack Scaff purified silicon by melting and recrystallizing ingots (Riordan and Hoddeson, 1997)...

Table of contents

• Cover
• Half Title
• Title Page
• Copyright Page
• Dedication
• Contents
• Preface to the Second Edition
• Preface to the First Edition
• Authors
• Abbreviations
• List of Elements by Symbol
• Chapter 1: Semiconductor Basics
• Chapter 2: Defect Classifications
• Chapter 3: Interfaces and Devices
• Chapter 4: Crystal Growth and Doping
• Chapter 5: Electronic Properties
• Chapter 6: Vibrational Properties
• Chapter 7: Optical Properties
• Chapter 8: Thermal Properties
• Chapter 9: Electrical Measurements
• Chapter 10: Optical Spectroscopy
• Chapter 11: Particle-Beam Methods
• Chapter 12: Microscopy and Structural Characterization
• Appendices
• Physical Constants
• Index