Delft University of Technology Ultra-thin mems fabricated tynodes for electron multiplication Prodanovic, Violeta DOI 10.4233/uuid:1f889837-0d94-415c-8137-6065c0a44245 Publication date 2019 Document Version Final published version Citation (APA) Prodanovic, V. (2019). Ultra-thin mems fabricated tynodes for electron multiplication. https://doi.org/10.4233/uuid:1f889837-0d94-415c-8137-6065c0a44245 Important note To cite this publication, please use the final published version (if applicable). Please check the document version above. Copyright Other than for strictly personal use, it is not permitted to download, forward or distribute the text or part of it, without the consent of the author(s) and/or copyright holder(s), unless the work is under an open content license such as Creative Commons. Takedown policy Please contact us and provide details if you believe this document breaches copyrights. We will remove access to the work immediately and investigate your claim. This work is downloaded from Delft University of Technology. For technical reasons the number of authors shown on this cover page is limited to a maximum of 10. ULTRA-THIN MEMS FABRICATED TYNODES FOR ELECTRON MULTIPLICATION 537226-L-sub01-bw-Frodanovic Processed on: 29-10-2019 PDF page: 1 537226-L-sub01-bw-Frodanovic Processed on: 29-10-2019 PDF page: 2 ULTRA-THIN MEMS FABRICATED TYNODES FOR ELECTRON MULTIPLICATION Proefschrift ter verkrijging van de graad van doctor aan de Technische Universiteit Delft, op gezag van de Rector Magnificus prof. dr. ir. T.H.J.J. van der Hagen, voorzitter van het College voor Promoties, in het openbaar te verdedigen op dinsdag 19 november 2019 om 15:00 uur door Violeta PRODANOVIC´ Master of Science in Electrical Engineering and Computer Science, Universiteit van Belgrado, Belgrado, Servië, geboren te Zvornik, Joegoslavië. 537226-L-sub01-bw-Frodanovic Processed on: 29-10-2019 PDF page: 3 Dit proefschrift is goedgekeurd door de promotor: prof. dr. ir. P.M.Sarro promotor: prof. dr. ir. H. van der Graaf Samenstelling promotiecommissie: Rector Magnificus, voorzitter Prof. dr. ir. P.M. Sarro, Technische Universiteit Delft Prof. dr. ir. H. van der Graaf, Technische Universiteit Delft Onafhankelijke leden: Prof. dr. J. Schmitz, Universiteit Twente Prof. dr. J.E.J. Schmitz, Technische Universiteit Delft Prof. dr. ir. P.Kruit, Technische Universiteit Delft Prof. dr. K. Desch, Universität Bonn, Duitsland Dr. G. Nutzel, Photonis, Frankrijk Keywords: Tynodes, ultra-thin membranes, timed-photon counter, secondary electron emission, atomic layer deposition Printed by: Ipskamp Front & Back: Cover design by Ipskamp and the author Copyright © 2019 by V. Prodanovi´c All rights reserved. No part of this thesis may be reproduced, stored in a retreival system, or transmitted in any form or by any means without the prior written permission of the copyright owner. ISBN 978-94-6384-085-9 An electronic version of this dissertation is available at http://repository.tudelft.nl/. 537226-L-sub01-bw-Frodanovic Processed on: 29-10-2019 PDF page: 4 And if you find her poor, Ithaka won’t have fooled you. C.P.Cavafy 537226-L-sub01-bw-Frodanovic Processed on: 29-10-2019 PDF page: 5 537226-L-sub01-bw-Frodanovic Processed on: 29-10-2019 PDF page: 6 CONTENTS List of Acronyms and Symbols xi Summary xv Samenvatting xvii 1 Introduction 1 1.1 Detection of light .............................. 2 1.2 TImed Photon Counter (TiPC) and MEMS fabricated tynodes . 4 1.3 Outline of the thesis............................. 7 References .................................... 7 2 Secondary electron emission and its role in photodetectors 9 2.1 Photomultiplier tubes............................ 10 2.1.1 Photocathodes ............................ 10 2.1.2 Dynodes and secondary electron emission (SEE) process . 12 2.2 Reflection secondary electron emission (RSEE) ............... 12 2.2.1 Materials with high reflective secondary electron yield (RSEY). 15 2.3 Working principle of TImed Photon Counter (TiPC) and tynodes . 17 2.4 Transmission secondary electron emission (TSEE) ............. 20 2.4.1 Materials with high transmission secondary electron yield (TSEY). 21 2.5 Charging of insulators............................ 22 2.5.1 Strategies to minimize charging in SEY measurements. 25 2.6 Conclusions................................. 27 References .................................... 27 3 Low Pressure Chemical Vapour Deposited Silicon Nitride Tynodes 33 3.1 LPCVD SiN ................................. 34 3.2 SiN tynodes ................................. 36 3.2.1 Layout of the tynodes ........................ 36 3.2.2 Fabrication process ......................... 36 3.3 Tools for the material characterization ................... 38 3.3.1 Wafer curvature method ....................... 39 3.3.2 Spectroscopic ellipsometry ..................... 41 3.3.3 Atomic force microscopy (AFM) ................... 42 3.3.4 X-ray Diffraction (XRD) ....................... 44 3.3.5 X-ray spectroscopy (XPS)....................... 44 3.3.6 Micromegas detector ........................ 45 3.3.7 Setup for SEE analysis ........................ 47 vii 537226-L-sub01-bw-Frodanovic Processed on: 29-10-2019 PDF page: 7 viii CONTENTS 3.4 Results and discussion ........................... 50 3.4.1 Residual stress ............................ 50 3.4.2 Thickness and optical properties................... 50 3.4.3 Surface morphology ......................... 51 3.4.4 Elemental composition and resistivity ................ 52 3.4.5 Secondary electron emission..................... 53 3.5 Conclusions................................. 54 References .................................... 55 4 Atomic Layer Deposited Alumina Tynodes 59 4.1 ALD ..................................... 60 4.2 ALD alumina ................................ 61 4.2.1 Deposition method ......................... 62 4.2.2 Fabrication of alumina tynodes ................... 63 4.3 Results ................................... 65 4.3.1 Residual stress ............................ 65 4.3.2 Thickness and optical properties................... 66 4.3.3 Elemental composition ....................... 67 4.3.4 Surface morphology ......................... 68 4.3.5 Secondary electron emission..................... 69 4.4 Conclusions................................. 71 References .................................... 72 5 Atomic Layer Deposited Magnesium Oxide Tynodes 75 5.1 Magnesium oxide (MgO) .......................... 76 5.2 ALD magnesium oxide ........................... 76 5.3 Fabrication of ALD MgO tynodes ...................... 78 5.4 Characterization of ALD MgO films ..................... 78 5.4.1 Thickness, optical properties and residual stress ........... 78 5.4.2 Elemental composition ....................... 79 5.4.3 Surface morphology ......................... 80 5.4.4 Secondary electron emission..................... 82 5.5 Enhancement of SEY of ALD MgO tynodes ................. 83 5.5.1 Preparation of MgO films ...................... 84 5.5.2 Results and discussion ........................ 86 5.6 Conclusions................................. 94 References .................................... 95 6 Towards improved design of the tynodes 99 6.1 Other candidates for the tynode materials . 100 6.1.1 LPCVD SiC ..............................100 6.1.2 ALD AlN ...............................100 6.1.3 Ultrananocrystalline diamond (UNCD) . 101 6.1.4 Single crystalline silicon .......................103 537226-L-sub01-bw-Frodanovic Processed on: 29-10-2019 PDF page: 8 CONTENTS ix 6.2 Curved tynodes ...............................105 6.2.1 Fabrication of curved tynodes ....................105 6.2.2 Stacking of tynodes .........................108 6.2.3 Metal mesh between active tynode areas. 109 6.3 Conclusions.................................110 References ....................................111 7 Conclusion 113 7.1 Conclusions.................................114 7.2 Recommendations for future work .....................115 A Appendix A 117 B Appendix B 119 C Appendix C 121 Acknowledgements 125 List of Publications 129 537226-L-sub01-bw-Frodanovic Processed on: 29-10-2019 PDF page: 9 537226-L-sub01-bw-Frodanovic Processed on: 29-10-2019 PDF page: 10 LISTOF ACRONYMS AND SYMBOLS ± (Total) secondary electron yield ±m Maximum secondary electron yield BSEY Back-scattered electron yield Ea Electron affinity E First crossover energy of PEs for which ± 1 I Æ E Second crossover energy of PEs for which ± 1 II Æ Em Energy of primary electrons corresponding to maximum ± (±m) EPE Energy of primary electrons FSEY Forward-scattered electron yield REY Reflection electron yield (calculated as: REY RSEY BSEY ) Æ Å RSEY Reflection secondary electron yield TEY Transmission electron yield (calculated as: TEY T SEY F SEY ) Æ Å TSEY Transmission secondary electron yield Al2O3 Aluminium oxide, alumina AlN Aluminium nitride BCl3 Boront trichloride C2F6 Hexafluoroethane C2H2 Acetylene Cs Caesium CsI Caesium iodide DCS, SiH2Cl2 Dichlorosilane HCl Hydrogen chloride HF Hydrofluoric acid HNO3 Nitric acid KCl Potassium chloride KOH Potassium hydroxide Mg(Cp)2 Bis(cyclopentadienyl)magnesium Mg(CpEt)2 bis(ethylcyclopentadienyl)magnesium Mg(OH)2 Magnesium hydroxide xi 537226-L-sub01-bw-Frodanovic Processed on: 29-10-2019 PDF page: 11 xii LISTOF ACRONYMS AND SYMBOLS MgCO3 Magnesium carbonate MgO Magnesium oxide NH3 Ammonia SiC Silicon carbide SiH4 Silane SiN, Si3N4 Silicon nitride TMA, Al(CH3)3 Trimethylaluminium AFM Atomic force microscopy ALD Atomic layer deposition BSE Backscattered electron CMOS Complementary metal-oxide-semiconductor