Microwave plasma sources and methods in processing technology / Ladislav Bardos, Hana Barankova, Uppsala University, Uppsala, Sweden.

Includes bibliographical references and index.

Table of Contents
Foreword from the Authors ix

1 Basic Principles and Components in the Microwave Techniques and Power Systems 1

1.1 History in Brief – From Alternating Current to Electromagnetic Waves and to Microwaves 1

1.2 Microwave Generators 3

1.3 Waveguides and Electromagnetic Modes in Wave Propagation 5

1.3.1 The Cut-off Frequency and the Wavelength in Waveguides 7

1.3.2 Waveguides Filled by Dielectrics 9

1.3.3 Wave Impedance and Standing Waves in Waveguides 10

1.3.4 Coaxial Transmission Lines 12

1.3.5 Microwave Resonators 14

1.4 Waveguide Power Lines 14

1.4.1 Magnetron Tube Microwave Generator 16

1.4.2 Microwave Insulators 16

1.4.3 Impedance Tuners 17

1.4.4 Directional Couplers 19

1.4.5 Passive Waveguide Components – Bends, Flanges, Vacuum Windows 20

1.4.6 Tapered Waveguides and Waveguide Transformers 22

1.4.7 Power Loads and Load Tuners 23

1.4.8 Waveguide Phase Shifters 25

1.4.9 Waveguide Shorting Plungers 25

1.4.10 Coupling from Rectangular to Circular Waveguide: Resonant Cavities for Generation of Plasma 26

1.5 Microwave Oven – A Most Common Microwave Power Device 28

References 33

2 Gas Discharge Plasmas 37

2.1 Basic Understanding of the Gas Discharge Plasmas 37

2.2 Generation of the Plasma, Townsend Coefficients, Paschen Curve 40

2.3 Generation of the Plasma by AC Power, Plasma Frequency, Cut-off Density 43

2.4 Space-charge Sheaths at Different Frequencies of the Incident Power 50

2.5 Classification of Gas Discharge Plasmas, Effects of Gas Pressure, Microwave Generation of Plasmas 55

2.5.1 Classification of Gas Discharge Plasmas 55

2.5.2 Effects of the Gas Pressure on Particle Collisions in the Plasma 58

2.5.3 Microwave Generation of Plasmas 61

References 64

3 Interactions of Plasmas with Solids and Gases 67

3.1 Plasma Processing, PVD, and PE CVD 67

3.2 Sputtering, Evaporation, Dry Etching, Cleaning, and Oxidation of Surfaces 72

3.3 Particle Transport in Plasma Processing and Effects of Gas Pressure 75

3.3.1 Movements of Neutral Particles 76

3.3.2 Movements of Charged Particles 77

3.3 Effect of the Gas Pressure on the Plasma Processing 79

3.4 Afterglow and Decaying Plasma Processing 81

References 83

4 Microwave Plasma Systems for Plasma Processing at Reduced Pressures 85

4.1 Waveguide-Generated Isotropic and Magnetoactive Microwave Plasmas 85

4.1.1 Waveguide-Generated Isotropic Microwave Oxygen Plasma for Silicon Oxidation 87

4.1.2 ECR and Higher Induction Magnetized Plasma Systems for Silicon Oxidation 93

4.2 PE CVD of Silicon Nitride Films in the Far Afterglow 105

4.3 Microwave Plasma Jets for PE CVD of Films 111

4.3.1 Deposition of Carbon Nitride Films 115

4.3.2 Surfajet Plasma Parameters and an Arrangement for Expanding the Plasma Diameter 119

4.4 Hybrid Microwave Plasma System with Magnetized Hollow Cathode 122

References 129

5 Microwave Plasma Systems at Atmospheric and Higher Pressures 135

5.1 Features of the Atmospheric Plasma and Cold Atmospheric Plasma (CAP) Sources 136

5.2 Atmospheric Microwave Plasma Sources Assisted by Hollow Cathodes 140

5.2.1 Applications of the H-HEAD Plasma Source in Surface Treatments 144

5.3 Microwave Treatment of Diesel Exhaust 151

5.4 Microwave Plasma in Liquids 154

5.5 Microwave Plasma Interactions with Flames 157

5.6 Microwave Plasmas at Very High Pressures 161

References 162

6 New Applications and Trends in the Microwave Plasmas 169

References 176

7 Appendices 181

7.1 List of Symbols and Abbreviations 181

7.2 Constants and Numbers 188

Index 189

"The greatest discoveries and developments connected with the great names in the alternating current and related systems were dated already in early nineteenth century, see review [1.1]. However, an important basic invention was the battery, a source of electricity, disclosed by the Italian scientist Alessandro Volta in 1799. This simple source of a direct current (DC) allowed many important experiments with the electricity. In 1820 Danish physicist Hans Christian �rsted discovered an effect of electricity on the magnetic field and his findings were confirmed by experiments of French physicists Andre-Marie Ampere and Francoise Arago. The parallel wires with DC current visibly attracted or repelled each other according to the mutual current directions. However, an ability to generate electricity by the moving magnets and the corresponding principle of the electric induction was discovered in 1830 by English scientist Michael Faraday. These new effects based on the electric induction inspired Serbian-American electrical and mechanical engineer Nikola Tesla and led to his inventions of an alternating current (AC) generator used rotating magnetic field, his Tesla coil, the transformation of AC voltages to very high voltages or vice-versa, as well as other inventions patented at the end of 1887. Besides of his fundamental inventions Tesla is considered as a pioneer also in the radar technology, X-ray technology and remote control.

About the Author
Ladislav Bardos is a Professor at the Department of Electrical Engineering at Uppsala University. He received his PhD from the Institute of Plasma Physics at the Czech Academy of Sciences in 1978. In 1995 he obtained the highest scientific degree DrSc from Charles University in Prague. In 1984 he was awarded the Czechoslovak State Prize for his research achievements. In2019 he was awarded The EPS Plasma Physics Innovation Prize. Prof. Bardos designed, developed and patented several plasma sources for industrial applications. He is an active member of the Society of Vacuum Coaters in the U.S. and is also involved in the organization boards of AVS and ECS in the U.S.
Hana Barankova is a Professor at the Department of Electrical Engineering, Uppsala University. She is a research leader of the Plasma Group and co-inventor of a number of new plasma sources and processes. Prof. Barankova is Secretary of the Board of Directors at the Society of Vacuum Coaters in the US. She has a long experience in design, construction and applications of different discharge processes and reactors. She is a recipient of the Mentor Award by the Society of Vacuum Coaters (US) and was awarded the Plasma Physics Innovation Prize 2019 by the European Physical Society for technological, industrial and societal applications of research in plasma physics. She teaches several courses related to discharge plasmas, both at the Uppsala University and abroad, and supervises graduate students. For more than 20 years she has been teaching 3annual courses on plasma sources and apps in the US.