This book covers the state-of-the-art and the fundamentals of silicon wafer solar cells manufacturing, written by world-class researchers and experts in the field.
High quality and economic photovoltaic manufacturing is central to realizing reliable photovoltaic power supplies at reasonable cost. While photovoltaic silicon wafer manufacturing is at a mature, industrial and mass production stage, knowing and applying the fundamentals in solar manufacturing is essential to anyone working in this field.
This is the first book on photovoltaic wet processing for silicon wafers, both mono- and multi-crystalline. The comprehensive book provides information for process, equipment, and device engineers and researchers in the solar manufacturing field. The authors of the chapters are world-class researchers and experts in their field of endeavor. The fundamentals of wet processing chemistry are introduced, covering etching, texturing, cleaning and metrology. New developments, innovative approaches, as well as current challenges are presented. Benefits of reading the book include: - The book includes a detailed discussion of the important new development of black silicon, which is considered to have started a new wave in photovoltaics and become the new standard while substantially lowering the cost. - Photovoltaics are central to any country’s “New Green Deal” and this book shows how to manufacture competitively. - The book’s central goal is to show photovoltaic manufacturing can be done with enhanced quality and lowering costs.
Audience
Engineers, chemists, physicists, process technologists, in both academia and industry, that work with photovoltaics and their manufacture.
Table of Contents
Preface ix
1 Metal-Assisted Chemical Etching of Silicon: Origin, Mechanism, and Black Silicon Solar Cell Applications 1
Chenliang Huo, Jiang Wang, Haoxin Fu and Kui-Qing Peng
1.1 Introduction 1
1.2 History and Mechanism of Metal-Assisted Chemical Etching of Silicon 3
1.2.1 History of Metal-Assisted Chemical Etching of Silicon 3
1.2.2 Mechanism of Metal-Assisted Chemical Etching of Silicon 7
1.3 Fabrication and Optical Properties of Black Silicon by MacEtch of Silicon 12
1.3.1 Background of Black Silicon by MacEtch of Silicon 12
1.3.2 Developments on MacEtch Black Silicon Fabrication Techniques 14
1.4 Photovoltaic Solar Cell Applications of MacEtch Black Silicon 17
1.4.1 Silicon Nanowire/Nanohole-Based MacEtch Black Silicon for Photovoltaic Solar Cells 17
1.4.2 Alkaline Treatment Modified MacEtch Black Silicon for Photovoltaic Solar Cells 19
1.4.3 MacEtch Black Silicon for Diamond Sawed mc-Si Photovoltaic Solar Cells 22
1.4.4 Copper-MacEtch Inverted Pyramid Black Silicon for Photovoltaic Solar Cells 24
1.5 Concluding Remarks 27
Acknowledgements 29
References 29
2 Alkaline Texturing 43
Vanesa Fano, Juan Carlos Jimeno, José Rubén Gutiérrez and Mª Velia Rodríguez
2.1 Introduction to Alkaline Texturing 43
2.2 Pyramid Formation 46
2.2.1 Main Requirements and Theories 46
2.2.2 Optimizing the Texturing: Shape and Size Aspects 50
2.3 Chemical Mixtures Used in the Alkaline Texturing 51
2.3.1 Overview of Chemistries Used for Alkaline Texturing 51
2.3.2 Most Common Chemistries 52
2.3.3 Other Mixtures 53
2.3.4 Challenges to Develop Alkaline Texturing Recipes 54
2.4 Mechanisms of Alkaline Texturing, Important Parameters Involved in Alkaline Texturing 54
2.4.1 Influence of Alkaline Concentration 54
2.4.2 Additives 57
2.4.2.1 IPA 58
2.4.2.2 Other Additives 60
2.4.3 Silicates 62
2.4.4 Temperature 65
2.4.5 pH 66
2.4.6 Process Time 66
2.4.7 Agitation 68
2.4.8 Dissolved Gases 71
2.5 Surface Conditioning Prior to Alkaline Texturing 71
2.6 Problems Associated to Alkaline Texturing 73
References 75
3 Advanced Texturing 83
Lixia Yang, Yaoping Liu and Xiaolong Du
3.1 Introduction to Advanced Texturing 83
3.2 History and Definition of Metal-Assisted Chemical Etching 84
3.3 Mechanisms of Metal-Assisted Chemical Etching 85
3.3.1 Reactions of Metal-Assisted Chemical Etching 85
3.3.2 Redox System of Metal-Assisted Chemical Etching 87
3.4 Methods of Metal-Assisted Chemical Etching 90
3.4.1 Two-Step Metal-Assisted Chemical Etching Process 90
3.4.2 One-Step Metal-Assisted Chemical Etching 93
3.5 Copper-Assisted Chemical Etching 99
3.5.1 Copper-Assisted Chemical Etching of c-Si 99
3.5.2 Copper-Assisted Chemical Etching of m-Si 107
3.6 Conclusion 108
References 109
4 Wet Chemical Cleaning for Industrial Application 115
Florian Buchholz, Eckard Wefringhaus and Martin Plettig
4.1 Introduction 116
4.2 Status of Production Technology in Solar Cell Manufacturing 117
4.3 Wet Chemical Process Technology 119
4.3.1 Tools 119
4.3.2 Etching 123
4.3.3 Cleaning 125
4.3.4 Rinsing and Drying 127
4.3.5 Process Integration 128
4.4 Contamination Management 130
4.4.1 Measurement of Surface Contamination 132
4.4.2 As-Cut Wafer 135
4.4.3 Alkaline Etching 137
4.4.4 Contaminants of Interest and Their Threshold Values 142
4.4.5 Organic Contamination 146
4.4.6 Application: Optimization of HF/O3 Cleaning Process 147
4.5 Cost Considerations 150
4.6 Conclusion 154
Acknowledgments 155
References 155
5 Analytical Techniques for Wet Processing 161
Stefanie Wahl and Sylke Meyer
5.1 Introduction 161
5.1.1 The Importance of Chemical Analysis on Silicon Surfaces 162
5.1.2 Impact of Surface Contaminations on the Solar Cell Process 163
5.1.3 Methods for the Determination of Surface Contaminations 164
5.2 Metal Analysis by ICP-MS 167
5.2.1 Sandwich Method 168
5.2.2 Droplet Scan Method 169
5.2.3 Immersion Method 170
5.2.4 Sequential Etching Methods 171
5.3 Determination of Organic Contaminations 173
5.3.1 Se-toc 174
5.3.2 Contact Angle Mapping 175
5.3.3 TD-GC-MS 177
Acknowledgments 179
References 179
Index 181
