Universidad Autónoma de Madrid Doctoral Thesis New approaches to anti-multipactor coatings for space applications Author Supervisor Valentin C. Nistor Dr. Luis Galan Estella A thesis submitted in fulfilment of the requirements for the degree of Doctor of Philosophy in Advanced Materials and Nanotechnology Departamento de Física Aplicada, Facultad de Ciencias November 2015 1 “Dedicated to my family” 2 3 Acknowledgements Me gustaría agradecer en primer lugar a Prof. Dr. Luis Galán Estella, el director de esta tesis, por los conocimientos científicos y el apoyo que me ha trasmitido, por la valiosísima ayuda y cariño que he recibido de su parte y su dedicación profesional durante todos estos años, que han hecho posible la realización de esta tesis, así como su gran mérito en la redacción de este manuscrito. También me gustaría agradecer a la Dra. Isabel Montero por su motivación, disponibilidad y los buenos consejos cuando más lo he necesitado. Quiero también expresar mis más sinceros agradecimientos a José Antonio por haberme iniciado en las técnicas experimentales durante mi inicio en el doctorado y por su gran apoyo y paciencia. Finalmente quiero agradecer a todas las personas de mi entorno profesional y personal que, de una forma u otra, han enriquecido mi vida durante la estancia en la Universidad Autónoma. 4 5 Contents Table of Contents Acknowledgements .......................................................................................................... 4 Contents ............................................................................................................................ 6 Abbreviations ................................................................................................................. 10 Acronyms ....................................................................................................................... 12 Resumen ......................................................................................................................... 14 Chapter 1 ........................................................................................................................ 18 Introduction .................................................................................................................... 18 1.1 Secondary Electron Emission and Multipactor Effect................................. 18 1.2 Technological research of UAM-CSIC-ESA-Tesat and Spain National Plan 20 1.2.1 Background research ..................................................................................... 20 1.2.2 Main research of this thesis - ESA AO 4025 CCN-2 project ........................ 23 1.2.3 Extended research for ESA ITI B00011822 project ...................................... 24 1.3 Scientific research and technological applications ...................................... 25 1.4 Motivation and scope of this work .............................................................. 27 Bibliography chapter 1 ................................................................................................... 30 Chapter 2 ........................................................................................................................ 34 Basic Principles .............................................................................................................. 34 2.1 Secondary Electron Emission ................................................................................... 34 2.1.1 SEY: definition and properties ...................................................................... 34 2.1.2 SEY testing .................................................................................................... 39 2.1.3 Experimental evidences of secondary emission yield decrease with surface roughness ................................................................................................................ 43 2.1.4 Explanation of SEY suppression by surface roughness ................................ 48 2.2 Multipactor Effect..................................................................................................... 52 2.2.1 Multipactor Effect in Parallel Plate geometry ............................................... 52 2.2.2 Insertion Loss of a RF waveguide ................................................................. 57 2.2.3 RF Surface resistance .................................................................................... 60 2.2.4 A Layered Model for RF surface resistance calculation ............................... 64 Bibliography chapter 2 ................................................................................................... 74 Chapter 3 ........................................................................................................................ 80 Magnetron sputtering of structured copper .................................................................... 80 3.1 Background research on Structured Zone Model (SZM) ......................................... 80 6 3.2. Experimental technique and setup ........................................................................... 84 3.3. Surface characterization .......................................................................................... 85 3.3.1 Optical analysis ............................................................................................. 85 3.3.2. Scanning electron microscopy (SEM) analysis ............................................ 87 3.3.3 X-ray photon spectroscopy (XPS) analysis ................................................... 89 3.3.4 Electron dispersive X-ray spectroscopy (EDX) measurements .................... 93 3.3.5 Secondary electron yield (SEY) measurements ............................................ 93 3.3.6 X-ray diffraction (XRD) analysis .................................................................. 95 Bibliography chapter 3 ................................................................................................... 98 Chapter 4 ...................................................................................................................... 100 Flash thermal direct evaporation (black metals) .......................................................... 100 Background ................................................................................................................... 100 4.1 Technique description and experimental setup ...................................................... 100 4.2 Surface analysis ...................................................................................................... 102 4.2.1 SEM/AFM analysis and SEY results........................................................... 102 4.2.2 X-ray photon spectroscopy (XPS) measurements and results ..................... 105 4.2.3. Aging effects and recovery of the surface properties ................................. 106 4.3 Conclusions ............................................................................................................ 107 Bibliography chapter 4 ................................................................................................. 108 Chapter 5 ...................................................................................................................... 110 Nano-structured surfaces by masked preferential ion sputtering ................................. 110 5.1 Background research .............................................................................................. 110 5.2 Evaluation of material type..................................................................................... 111 5.3 Preparation technique and experimental setups...................................................... 113 5.4 Description of samples ........................................................................................... 116 5.5 Surface morphology (SEM) of Au-Ti, Ag-Ti and Ag-Mo ..................................... 117 5.6 SEY measurements and results............................................................................... 119 5.7 Quantitative XPS and EDX analysis ...................................................................... 120 5.7.1 Surface composition analysis of gold-titanium ........................................... 120 5.7.2 Surface composition analysis of silver-titanium ......................................... 122 5.8 Conclusions ............................................................................................................ 124 Bibliography chapter 5 ................................................................................................. 126 Appendix: Yield Ratios for Masking Preferential Sputtering ...................................... 127 Chapter 6 ...................................................................................................................... 130 Glancing angle deposition (GLAD) ............................................................................. 130 6.1. Technique evaluation ............................................................................................. 130 6.1.1. General description of GLAD technique .................................................... 131 7 6.1.2 Experimental setup ...................................................................................... 133 6.2. Experimental results .............................................................................................. 134 6.2.1 SEY measurements and SEM analysis ........................................................ 134 6.2.2 Surface characterization