Electronic Materials

302 Pages·1990·8.28 MB·English

by  L. A. A. Warnes (auth.), L. A. A. Warnes (eds.)

Electronic Materials
Electronic Materials
L. A. A. Warnes
Department of Electronic and Electrical Engineering
Loughborough University of Technology
VAN NOSTRAND REINHOLD
________ New York
ISBN-13: 978-1-4615-6895-7 e-ISBN-13: 978-1-4615-6893-3
DOl: 10.1007/978-1-4615-6893-3
Copyright © 1990 by L. A. A. Warnes
Softcover reprint of the hardcover 1s t edition 1990
All rights reserved. No part of this work covered by the
copyright hereon may be reproduced or used in any form or by
any means-graphic, electronic, or mechanical, including
photocopying, recording, taping, or information storage and
retrieval systems-without written permission of the publisher..
Published in the United States of America by
Van Nostrand Reinhold
115 Fifth Avenue
New York, New York 10003
Distributed in Canada by
Nelson Canada
1120 Birchmount Road
Scarborough, Ontario MIK 5G4, Canada
Published in Great Britain by
Macmillan Education Ltd
Houndmills, Basingstoke, Hampshire RG21 2XS
and London
16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1
Library of Congress Cataloging-in-Publication Data
Warnes, L.A.A.
Electronic materials/L.A.A. Warnes.
p. cm.
Includes index
1. Electronics-Materials. I. Title
TK7871.W34 1990
621.381-dc20
90-40593
CIP
Contents
x
h~
Frequently-used Physical Constants xi
1 The Structure of Solids 1
1.1 Ideal Crystal Structures 1
1.1.1 The Close-packing of Spheres 1
1.1.2 The Lattice and the Basis 2
1.1.3 The Unit Cell 3
1.1.4 Miller Indices 6
1.2 Defects in Crystalline Solids 8
1.2.1 Thermal Vibrations 8
1.2.2 Zero-dimensional (Point) Defects 8
1.2.3 One-dimensional (Line) Defects: Dislocations 12
1.2.4 Two-dimensional Defects 20
1.2.5 Three-dimensional Defects 21
1.3 Binary Phase Diagrams 21
1.3.1 Gibbs's Phase Rule 21
1.3.2 The Lever Rule 23
1.3.3 Eutectics 24
Problems 26
2 The Classical Theory of Electrical Conduction 32
2.1 Drude's Free Electron Theory 34
2.1.1 The Drift Velocity, Mobility and Ohm's Law 34
2.1.2 An Estimate of Mobility and Drift Velocity 36
2.1.3 The Mean Free Path 37
2.2 The Hall Effect 38
2.2.1 The Hall Probe 40
2.3 The Wiedemann-Franz Law 41
v
VI Contents
2.4 Matthiessen's Rule 43
2.5 Electromagnetic Waves in Solids 46
2.5.1 'Low' Frequencies 46
2.5.2 The Skin Depth 49
2.6 The Plasma Frequency 50
2.6.1 An Example 53
2.6.2 Plasma Oscillations: Plasmons 53
2.7 Failures of Classical Free Electron Theory 54
2.7.1 The Specific Heat of Metals 54
2.7.2 The Dependence of Electrical Conductivity on
Temperature 55
Problems 56
3 The Quantum Theory of Electrons in Solids 61
3.1 Schroedinger's Equation 61
3.2 The Particle in a Potential Well 62
3.3 The Pauli Exclusion Principle 63
3.4 The Fermi Energy 64
3.5 Fermi-Dirac Statistics 66
3.6 The Specific Heat of a Free Electron Gas 68
3.7 The Penney-Kronig Model 68
3.8 Energy Bands 70
3.8.1 The Effective Mass 72
3.8.2 Brillouin Zones 74
3.8.3 The Fermi Surface 75
3.8.4 The Density of States 77
3.9 Insulators, Semiconductors and Conductors 80
Problems 82
4 Charge Carriers in Semiconductors 84
4.1 Intrinsic Conduction in Semiconductors 84
4.2 Extrinsic Conduction in Semiconductors 88
4.2.1 Compensation 90
4.2.2 The Fermi Level in Extrinsic Semiconductors 90
4.3 p-n Junctions 94
4.3.1 The Einstein Relation 96
4.3.2 The Depletion Region 97
4.3.3 The Rectifier Equation 102
4.3.4 Junction Breakdown 104
4.4 The Bipolar Junction Transistor 105
4.5 The MOSFET 106
4.6 Measurement of Semiconductor Properties 109
4.6.1 Conductivity and Type 109
4.6.2 The Mobility and Lifetime 110
Contents Vll
4.6.3 The Hall Coefficient 111
4.6.4 The Carrier Concentration 112
4.6.5 The Effective Mass 112
4.6.6 The Energy Gap 114
Problems 114
5 VLSI Technology 118
5.1 A Quick Overview of the IC Production Process 119
5.2 Crystal Growth and Wafer Production 119
5.2.1 Segregation 124
5.3 Epitaxy 124
5.3.1 The Evaluation of Epitaxial Layers 127
5.4 Oxidation 128
5.5 Dielectric and Polysilicon Deposition 130
5.5.1 Dielectric Characterization 132
5.6 Diffusion 133
5.6.1 Erfc Diffusion 133
5.6.2 Gaussian Diffusion 135
5.6.3 Diffusion Profile Measurement 136
5.7 Ion Implantation 137
5.7.1 Annealing Implanted Layers 141
5.8 Lithography 142
5.9 Metallization 144
5.9.1 Contacts 145
5.9.2 Junction Spiking 146
5.9.3 Electromigration 147
5.10 Assembly and Packaging 148
5.11 Beyond Silicon 150
Problems 151
6 Magnetic Phenomena 155
6.1 Magnetic Units 155
6.2 Types of Magnetic Order 156
6.3 The Hysteresis Loop 158
6.4 The Saturation Polarization 160
6.4.1 The Change in Saturation Polarization with
Temperature 162
6.5 Anisotropy Energy 165
6.5.1 Magnetocrystalline Anisotropy 165
6.5.2 Shape Anisotropy 166
6.6 Magnetic Domains 168
6.6.1 Domain Walls 168
6.6.2 Single-domain Particles 170
6.6.3 Hysteresis of Single-domain Particles 172
Vlll Contents
6.7 The Maximum Energy Product 174
6.8 Hysteresis in Multi-domain Magnetic Materials 177
6.8.1 The Initial Susceptibility 178
6.8.2 The Initial Magnetization Curve 180
6.9 Magnetostriction 181
Problems 182
7 Magnetic Materials and Devices 186
7.1 Soft Magnetic Materials 186
7.1.1 Transformer Core Materials 186
7.1.2 Soft Ferrites 189
7.1.3 The Production Technology of Soft Ferrites 192
7.2 Materials in Magnetic Recording 197
7.3 Magnetic Bubbles 199
7.4 Microwave Devices 201
7.4.1 The Isolator 201
7.4.2 Circulators 203
Problems 204
8 Dielectrics 207
8.1 The Electric Polarization 207
8.2 The Dielectric Constant or Relative Permittivity 207
8.3 Types of Polarization 209
8.3.1 Electronic Polarization 210
8.3.2 Orientational Polarization 211
8.3.3 The Total Polarization 212
8.4 The Local Field in a Dielectric 212
8.5 The Clausius-Mossotti Relation 213
8.5.1 The Refractive Index 214
8.6 Energy Absorption in Dielectrics 215
8.6.1 Dielectric Relaxation: The Debye Equation 216
8.6.2 The Loss Tangent 217
8.6.3 An Example of Capacitor Losses 219
8.7 Dielectric Breakdown 220
8.8 Ferroelectrics 221
8.8.1 The Catastrophe Theory 222
8.8.2 Uses of Ferroelectrics 223
Problems 224
9 Materials for Optoelectronics 227
9 .1 Light-emitting Diodes (LEDs) 227
9.1.1 LEDs for Displays 228
9.1.2 Signal LEDs 233
Contents IX
9.2 Solid-state Lasers 235
9.2.1 Output Characteristics of Solid-state Lasers 238
9.3 Optical Fibres 242
9.3.1 Step-index Fibres 243
9.3.2 Graded-index Fibres 244
9.3.3 Intramodal Dispersion 245
9.3.4 Attenuation in Optical Fibres 246
9.3.5 The Manufacture of Optical Fibres 247
9.4 Signal Detectors 249
9.4.1 PIN Diodes 249
9.4. 2 Avalanche Photodiodes 252
9.4.3 Phototransistors 253
9.5 The Solar Cell 254
9.5.1 Choice of Material 256
9.6 Displays 257
9.6.1 The Cathode Ray Tube (CRT) 257
9.6.2 Liquid Crystal Displays 258
9.7 Integrated Optics? 260
9.7.1 The Optical Switch 260
Problems 261
10 Superconductors 264
10.1 The Economics of Superconductivity 264
10.2 The Phenomenology of Superconductivity 265
10.3 Characteristic Lengths 269
10.3.1 Critical Fields 269
10.4 BCS Theory 270
10.5 The Josephson Effect 271
10.6 High-temperature Ceramic Superconductors 272
10.7 Applications of Superconductivity 273
Problems 274
Further Reading 276
Appendix: The Periodic Table of the Elements 280
Index 282
Preface
The importance of materials science for the progress of electronic techno
logy has been apparent to all since the invention of the transistor in 1948,
though that epoch-making event was the result of far-sighted research
planning by Bell Laboratories dating from a decade or more before: no
mere chance discovery, therefore, but the fruition of work which allotted
at its inception a vital role to materials. The transistor is now very old hat,
but new materials developments are continually triggering fresh develop
ments in electronics, from optical communications to high-temperature
superconductors.
Electronic engineers are now given at least two courses in materials as
part of their degree programme. This book arose from a series of forty
lectures the author gave to the third year students on the Extended
Honours Degree Course in Electronic and Electrical Engineering at
Loughborough University, though additional elementary material has
been included to make the book suitable for first year students. The biggest
problem in such a course is deciding what must be left out, and this I am
afraid I shirked by leaving out all those areas which I was not familiar with
from my days in the Ministry of Aviation, the semiconductor device
industry and as a graduate student and research worker. I hope that what
remains is sufficiently catholic. Where possible I have tried to use the
problems at the end of each chapter to expand the text, but stock questions
are needed also. Quite a number of the problems are those which arose in
practical situations: they are often more interesting because of the manner
of their genesis, but also more difficult.
To my wife, Irene, I offer my thanks for putting up with this for longer
than I like to recall.
x
Frequently-used Physical
Constants
c, the speed of light in a vacuum 3.00 X 108 mls
- e, the electronic charge - 1.60 X 10- 19 C
g, the acceleration due to gravity 9.81 m/s2
h, Planck's constant 6.63 X 10-34 Is
h, Planck's constant divided by 21T 1.055 X 10-34 Is
kB' Boltzmann's constant 1.38 X 10-23 11K
mo, the electronic rest mass 9.11 X 10-31 kg
at., the standard atmosphere 1.013 X 105 Pa
a.m.u., the atomic mass unit 1.66 X iO- 27 kg
EO, the permittivity of a vacuum 8.85 X 10- 12 F/m
fLo, the magnetic constant 41T X 10-7 Him
f.LB, the Bohr magneton 9.27 X 10-241fT
xi