Characterization in Silicon Processing

by Yale E. Strausser

Overview

Characterization in Silicon Processing reviews characterization techniques of interest to silicon processing engineers. Increasingly stringent materials requirements, such as decreasing barrier film thicknesses, have prompted a need for improved materials quality and performance. In order to meet these high standards, process engineers must be familiar with modern techniques for characterization of microstructure and the relationship of microstructure to surface preparation and deposition techniques. This book covers the most recent advances in characterization, including: monitoring the effectiveness of surface cleaning processes such as morphology, residues, and chemical reactions; determining the amount of silicon consumption during barrier film and silicide growth on silicon; monitoring grain size and grain growth in aluminum—important for electromigration effects and in lithography; and silicon selective epitaxial growth.

Product Details

ISBN-13:	9781606501092
Publisher:	Momentum Press
Publication date:	12/01/2009
Pages:	240
Product dimensions:	6.10(w) x 9.30(h) x 0.70(d)

Table of Contents

Preface to the Reissue of the Materials Characterization Series ix

Preface to Series x

Preface to the Reissue of Characterization in Silicon Processing xi

Preface xii

Contributors xiv

Application of Materials Characterization Techniques to Silicon Epitaxial Growth

1.1 Introduction 1

1.2 Silicon Epitaxial Growth 2

Basic Chemical Reactions 2

Precleaning Considerations 3

Reactor Types 3

1.3 Film and Process Characterization 4

Crystal Quality 4

Preclean Quality 6

Thickness 9

Dopant Concentration and Dopant Profiling 12

1.4 Selective Growth 14

Basic Process Considerations 14

Defect Density and Growth Morphology 15

Preclean Quality 18

Thickness 18

1.5 Si_1-xGe_x Epitaxial Growth 18

Material Considerations 18

Reactor Types 19

1.6 Si_1-xGe_x Material Characterization 20

Composition and Thickness 20

Growth Morphology 22

Lattice Strain and Critical Thickness 23

Relaxation Kinetics 24

Bandgap Measurements 24

Interracial Abruptness and Outdiffusion 25

Impurity Profiles 25

1.7 Summary 26

Polysilicon Conductors

2.1 Introduction 32

2.2 Deposition 33

Surface Preparation 34

Nucleation and Growth 35

Postgrowth Analysis 38

High-Quality Polysilicon 42

Integrated Circuit Fabrication Issues 43

2.3 Doping 45

Dopant Distribution 45

Deglaze 46

Ion Implantation Doping 46

2.4 Patterning 47

Lithography 47

Etching 47

2.5 Subsequent Processing 48

Polycides 48

Dielectric Encapsulation 49

Silicides

3.1 Introduction 53

3.2 Formation of Silicides 57

Sheet Resistance Measurements 57

Rutherford Backscattering Measurements 60

X-Ray Diffraction Measurements 72

Ellipsometric Measurements 74

3.3 The Silicide-Silicon Interface 76

3.4 Oxidation of Silicides 82

3.5 Dopant Redistribution During Silicide Formation 84

3.6 Stress in Silicides 87

3.7 Stability of Silicides 90

3.8 Summary 92

Aluminum-And Copper-Based Conductors

4.1 Introduction 96

History 96

4.2 Film Deposition 98

Techniques 98

Problems with Deposition 101

4.3 Film Growth 104

Substrate Surface Properties 104

Surface Preparation 107

Film Formation 108

Microstructure 110

Patterning and Etching 110

4.4 Encapsulation 113

4.5 Reliability Concerns 114

Tungsten-Based Conductors

5.1 Applications for ULSI Processing 121

5.2 Deposition Principles 122

5.3 Blanket Tungsten Deposition 123

Film Thickness 123

Film Conformality 124

Film Resistivity 124

Film Stress 125

Surface Roughness 126

Film Microstructure 127

5.4 Selective Tungsten Deposition 127

Selectivity Breakdown 129

Substrate Interaction 131

Barrier Films

6.1 Introduction 138

6.2 Characteristics of Barrier Films 139

6.3 Types of Barrier Films 140

6.4 Processing Barrier Films 140

Inert Sputtering 141

Reactive Sputtering 141

Chemical Vapor Deposition 142

Nitridation and Rapid Thermal Annealing 143

6.5 Examples of Barrier Films 143

Titanium Thin Films 144

Tungsten-Titanium Thin Films 149

Titanium Nitride 151

6.6 Summary 163

Appendix: Technique Summaries

1 Auger Electron Spectroscopy (AES) 169

2 Ballistic Electron Emission Microscopy (BEEM) 170

3 Capacitance-Voltage (C-V) Measurements 177

4 Deep Level Transient Spectroscopy (DLTS) 179

5 Dynamic Secondary Ion Mass Spectrometry (Dynamic SIMS) 181

6 Electron Beam Induced Current (EBIC) Microscopy 182

7 Energy-Dispersive X-Ray Spectroscopy (EDS) 188

8 Focused Ion Beams (FIBs) 189

9 Fourier Transform Infrared Spectroscopy (FTIR) 193

10 Hall Effect Resistivity Measurements 194

11 Inductively Coupled Plasma Mass Spectrometry (ICPMS) 196

12 Light Microscopy 197

13 Low-Energy Electron Diffraction (LEED) 198

14 Neutron Activation Analysis (NAA) 199

15 Optical Scatterometry 200

16 Photoluminescence (PL) 201

17 Raman Spectroscopy 202

18 Reflection High-Energy Electron Diffraction (RHEED) 203

19 Rutherford Backscattering Spectrometry (RBS) 204

20 Scanning Electron Microscopy (SEM) 205

21 Scanning Transmission Electron Microscopy (STEM) 206

22 Scanning Tunneling Microscopy and Scanning Force Microscopy (STM and SFM) 207

23 Sheet Resistance and the Four Point Probe 208

24 Spreading Resistance Analysis (SRA) 217

25 Static Secondary Ion Mass Spectrometry (Static SIMS) 225

26 Surface Roughness: Measurement, Formation by Sputtering Impact on Depth Profiling 226

27 Total Reflection X-Ray Fluorescence Analysis (TXRF) 227

28 Transmission Electron Microscopy (TEM) 228

29 Variable-Angle Spectroscopic Ellipsometry (VASE) 229

30 X-Ray Diffraction (XRD) 230

31 X-Ray Fluorescence (XRF) 231

32 X-Ray-Photoelectron Spectroscopy (XPS) 232

Index 233

Editorial Reviews

Reviews techniques by which silicon processing engineers working with semiconductors can meet the demands for improved material quality and performance made necessary by increasingly stringent requirements, such as decreasing barrier film thicknesses. Among the techniques described are monitoring the effectiveness of surface cleaning processes; determining the amount of silicon consumption during barrier film and silicide growth; and silicon selective epitaxial growth. Annotation c. Book News, Inc., Portland, OR (booknews.com)

Booknews