Characterization of Semiconductor Materials - Principles and Methods, Volume 1

240 Pages·1989·10.708 MB·English

by  McGuire, G.E.(eds.)

CHARACTERIZATION
OF SEMICONDUCTOR
MATERIALS
Principles and Methods
Volume I
Edited by
Gary E. McGuire
Microelectronics Center of North Carolina
Research Triangle Park, North Carolina
NOY ES PUBLlCATlONS
ParkR idy, New Jersey,U .S.A.
Copyright @ 1989 by Noyes Publications
No part of this book may be reproduced or utilized in
any form or by any means, electronic or mechanical,
including photocopying, recording or by any informa-
tion storage and retrieval system, without permission
in writing from the Publisher.
Library of Congress Catalog Card Number: 89-30273
ISBN: O-8155-1200-7
Printed in the United States
Published ‘in the United States of America by
Noyas Publications
Mill Road, Park Ridge, New Jersey 07656
10987654321
Library of Congress Cataloging-in-Publication Data
Characterization of semiconductor materials : principles and methods I
edited by Gary E. McGuire.
p. cm.
Bibliography: v.1. p.
ISBN o-8155-1200-7 (v. 1) :
1. Semiconductors--Handbooks, manuals, etc.
QC611.45.C42 1989
621.3815’2~-dc19 89-30273
CIP
MATERIALS SCIENCE AND PROCESS TECHNOLOGY SERIES
Editors
Rointan F. Bunshah, University of California, Los Angeles (Materials
Science and Technology)
Gary E. McGuire, Microelectronics Center of North Carolina (Electronic
Materials and Processing)
DEPOSITION TECHNOLOGIES FOR FILMS AND COATINGS: by Roinfan F.
Bunshah et al
CHEMICAL VAPOR DEPOSITION IN MICROELECTRONICS: by ArthurSherman
SEMICONDUCTOR MATERIALS AND PROCESS TECHNOLOGY HANDBOOK:
edited by Gary E. McGuire
SOL-GEL TECHNOLOGY FOR THIN FILMS, FIBERS, PREFORMS, ELECTRON-
ICS AND SPECIALTY SHAPES: edited by Lisa A. Klein
HYBRID MICROCIRCUIT TECHNOLOGY HANDBOOK: by James J. Licari and
Leonard R. Enlow
HANDBOOK OF THIN FILM DEPOSITION PROCESSES AND TECHNIQUES:
edited by Klaus K. Schuegraf
IONIZED-CLUSTER BEAM DEPOSITION AND EPITAXY: by Toshinori Takagi
DIFFUSION PHENOMENA IN THIN FILMS AND MICROELECTRONIC MATE-
RIALS: edited by Devendra Gupta and Paul S. Ho
SHOCK WAVES FOR INDUSTRIAL APPLICATIONS: edited by Lawrence E. Murr
HANDBOOK OF CONTAMINATION CONTROL IN MICROELECTRONICS:
edited by Donald L. Tolliver
HANDBOOK OF ION BEAM PROCESSING TECHNOLOGY: edited by Jerome J.
Cuomo, Stephen M. Rossnagel, and Harold R. Kaufman
FRICTION AND WEAR TRANSITIONS OF MATERIALS: by PeterJ. B/au
CHARACTERIZATION OF SEMICONDUCTOR MATERIALS-Volume 1: edited
by Gary E. McGuire ,
SPECIAL MELTING AND PROCESSING TECHNOLOGIES: edited by G.K. Bhat
Related Titles
ADHESIVES TECHNOLOGY HANDBOOK: by Arthur H. Landrock
HANDBOOK OF THERMOSET PLASTICS: edited by Sidney H. Goodman
SURFACE PREPARATION TECHNIQUES FOR ADHESIVE BONDING: by Ray-
mond F. Wegman
Preface
In the last decade the semiconductor industry has grown significantly while
the technology for producing modern integrated devices has evolved rapidly.
Even in its infancy, semiconductor technology required materials that were
a challenge to analyze by available analytical techniques. Even though there
have been major advances in analytical instrumentation, there have been equal
if not more significant advances in semiconductor technology. This poses a
major challenge for anyone involved in the characterization of semiconductor
materials. This problem has many different facets. In order to produce an in-
tegrated circuit, it is necessary to start with a high purity semiconductor sub-
strate. In the numerous processing steps the wafer is heated in high purity
gases, etched in special solvents, coated with layers of metal and dielectric
films, and altered in controlled ways to produce the final device. At all phases,
the purity requirements are very demanding.
The analysis requirements in the semiconductor industry encompass all three
phases of materials: gases, liquids and solids. For solids, this includes the semi-
conducting substrate as well as metal, dielectric, and organic films. It is neces-
sary to measure ppm dopants and ppb adventitious impurities in bulk mate-
rials and in thin layers. In many instances, it is important to distinguish inter-
stitial and substitutional impurities. Surfaces, interfaces and bulk microstruc-
ture also play an important role in ultimate device performance. Device scaling
has been a major factor in the rapid evolution in the microbeam analysis cap-
abilities of many instruments. Elemental determination and chemical state
identification represent a large fraction of the analysis requirements, but, elec-
trical measurements are among the most sensitive means to measure parameters
that ultimately affect device performance. Research, development and manu-
facturing of semiconductor devices requires an extensive array of analytical
tools.
V
vi Preface
Most scientists and engineers working in the field are familiar with only a few
of the techniques available to them. In addition, many of the analytical tools
are never fully exploited because of a lack of understanding of all of the in-
formation they can provide. This set of volumes is intended to review the
basic principles of selected techniques and provide illustrative examples of
applications taken from the semiconductor industry. A wide range of ana-
lytical techniques is covered, although no attempt was made to be comprehen-
sive. For a variety of reasons the chapters were not grouped by subject matter
or application. Many of the chapters describe techniques that are used routinely
while others describe tools that are emerging or are very specialized research
tools. There are many review articles and shorter volumes which touch on many
aspects of this field. The authors’ desire is to provide a completed work that
is a unique resource for individuals working in this field.
Research Triangle Park, North Carolina Gary E. McGuire
June, 1989
Contents
1. ELECTRICAL CHARACTERIZATION OF SEMICONDUCTOR
MATERIALS AND DEVICES. ............................. .I
George N. Maracas and Dieter K. Schroder
Introduction. ..................................... .l
Four-Point Probe/Wafer Mapping ........................ .6
Defects ........................................ ..g
Recombination/Generation Lifetime. ..................... 10
Introduction. ................................... 10
Lifetime Characterization Techniques ................... 14
Recombination Lifetime. ........................ .15
Photoconductive Decay ....................... .I5
Open Circuit Voltage Decay ..................... 17
Surface Photovoltage ......................... .20
Generation Lifetime. ........................... .23
Pulsed MOS Capacitor ........................ .23
Deep Level Transient Spectroscopy. ..................... .25
Introduction. .................................. .25
DLTSTheory...................................2 5
Determination of Activation Energy, Capture Cross
Section, and Trap Concentration .................. .28
Trap Depth Profiling ........................... .31
DLTS Variations. ............................... .31
Optical DLTS. ............................... .31
Conductance DLTS ............................ .31
Current Transient Spectroscopy (CTS) ............... .32
Scanning DLTS (SDLTS) ........................ .32
Doping Profiling .................................. .33
Introduction. .................................. .33
Spreading Resistance Profiling ....................... .33
ix
x Contents
Capacitance-Voltage Profiling ....................... .35
Secondary Ion Mass Spectroscopy Profiling .............. .37
References. ..................................... .40
2. SECONDARY ION MASS SPECTROMETRY. .................. .48
Alan E. Morgan
Principle of SIMS ................................. .48
Methodology .................................... .52
Sputter Rate. .................................. .52
Degree of Ionization ............................. .54
Reactive Primary Ion Bombardment ................. .56
Flooding ................................... .60
Detection Limits. ............................... .63
Mechanism of Secondary Ion Formation .................. .65
Kinetic Emission. ............................... .66
Chemical Emission. .............................. .67
Cesium: Electron Tunneling Model ................. .67
Oxygen: Bond Breaking Model .................... .68
Molecular Ion Emission ........................... .70
information Available .............................. .71
Identification of Elements. ......................... .71
Natural Isotopic Abundances. ..................... .73
High Mass Resolution. .......................... .73
High Energy Secondary Ions ...................... .74
Quantitative Analysis. ............................ .75
Molecular SIMS. ................................ .78
Surface Imaging ................................ .84
Depth Profiling. ................................ .87
Dynamic Range. .............................. .87
Detection Limits. ............................. .%I
Depth Resolution ............................. .95
Problem Areas ............................... .99
Instrumentation .................................. 101
Primary Ion Gun. .............................. .102
Insulation Samples. ............................ 104
Secondary ton Extraction. ......................... 106
Mass Spectrometer. .............................. 108
Ion Detection. ................................ .I10
Complete Instruments ............................ 111
Summary. ..................................... .I13
References. .................................... .I 14
3. PHOTOELECTRON SPECTROSCOPY: APPLICATIONS TO
SEMICONDUCTORS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .I1 7
John H. Thomas, III
Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117
The Electron Photoemission Experiment. . . . . . . . . . . . . . . . . . 117
Trends in Instrumentation. . . . . . . . . . . . . . . . . . . . . . . . . . . . 120
Contents xi
Synchrotron Excitation ........................... 120
Small Spot Photoelectron Spectroscopy. ................ 122
Imaging Photoemission Microscopy. ................... 124
Profiling Structures ................................ 125
The Silicon Dioxide-Silicon Interface .................. 127
Schottky Barriers on Ill-V Compound Semiconductors. ...... 135
Silicon Processing and Surface Analysis. ................ 138
Conclusion. ..................................... 142
References. .................................... .143
4. ION/SOLID INTERACTIONS IN SURFACE ANALYSIS. .......... 147
Albert J. Bevolo
Introduction. ................................... .I47
Ion/Solid Interactions: Elemental Targets ................. 153
Introduction. ................................. .I53
Linear Cascade Theory of Sputtering. .................. 157
Ion/Solid Interactions: Multielement Targets. .............. 167
Mechanisms .................................. .I67
Preferential Sputtering .......................... 171
Surface Segregation ............................ 181
Collision Cascade Effects ........................ 183
Interplay of Mechanisms. ........................ 186
Experimental Results. ............................ 191
Cu-Ni Alloy Studies. ............................. 201
Depth Profiling. ................................. .212
Summary. ..................................... .231
References. .................................... .233
5. MOLECULAR CHARACTERIZATION OF DIELECTRIC FILMS BY
LASER RAMAN SPECTROSCOPY ........................ .242
Gregory J. Exarhos
Introduction. ................................... .242
Theory: Description of the Method .................... .244
Interpretation of Raman Spectra of Solids. ................ 249
Raman Instrumentation and Measurement Capability. ......... 254
Applications to Thin Film Characterization ................ 259
Substrate Interference ............................ 260
Thickness Measurements. ......................... .263
Microcrystallite Orientation. ........................ 265
Nondestructive Depth Profiling ...................... 266
Phase Composition Studies ........................ .268
Interfacial Studies ............................... 269
Stress Measurements ............................. 271
Laser-Induced Damage to Films. ..................... 272
Limitations of Raman Spectroscopy for Thin Film
Characterization ................................ .277
Advanced Raman Characterization Techniques. ............. 278
Interference Enhanced Raman Spectroscopy (IERS) ........ 278
xii Contents
Guided Wave Raman Spectroscopy. ................... 280
Resonance Fiaman Spectroscopy .................... .282
References. .................................... .283
6. CHARACTERIZATION OF SEMICONDUCTOR SURFACES BY
APPEARANCE POTENTIAL SPECTROSCOPY. ............... .289
Dev I?. Chopra and Anil R. Chourasia
Introduction. ................................... .289
Principle ...................................... .292
Experimental ................................... .296
Soft X-ray Appearance Potential Spectroscopy ............ 296
Auger Electron Appearance Potential Spectroscopy. ........ 298
Disappearance Potential Spectroscopy. ................. 299
Applications. ................................... .301
Electronic Structure of Semiconductors, Metals, and
Semiconductor-Metal Interfaces ..................... 301
Adsorption. .................................. .308
Extended Appearance Potential Fine Structure. ........... 311
Conclusions .................................... .318
Glossary of Symbols .............................. .320
References. .................................... .321
lNDEX..............................................328
1
Electrical Characterization of Semiconductor
Materials and Devices
George N. Maracas and Dieter K. Schroder
1. INTRODUCTION
Semiconductor materials have had to meet progressively more stringent
requirements as the density and performance of semiconductor devices has
increased. This trend will continue. The purity of the material, the dimensions of
the devices, and the electrical properties require higher precision in their
measurement and the ability to determine the device parameters to a resolution
and sensitivity that pushes measurement techniques to their very limit.
Semiconductor. measurements cover a broad range of techniques and disciplines.
After a brief listing of optical and physical/ chemical characterization methods we
give in this chapter a discussion of the general trend in electrical characterization
and present a few examples of the characterization techniques used today.
Semiconductor material and device characterization falls into three main
categories
Electrical characterization
l
Optical characterization
l
Physical/chemical characterization
l
Although this chapter deals with electrical characterization, we briefly mention
the other two to place them into their proper perspective.
Optical charactetization methods include
Optical microscopy
l
Ellipsometry
l
Photoluminescence (PL)
l
1