Bartolf Fluctuation Mechanisms in Superconductors

Nanowire Single-Photon Counters, Enabled by Effective Top-Down Manufacturing
1. Auflage 2016
ISBN: 978-3-658-12246-1
Verlag: Springer
Format: PDF
Kopierschutz: 1 - PDF Watermark

E-Book, Englisch, 336 Seiten

Holger Bartolf discusses state-of-the-art detection concepts based on superconducting nanotechnology as well as sophisticated analytical formulæ that model dissipative fluctuation-phenomena in superconducting nanowire single-photon detectors. Such knowledge is desirable for the development of advanced devices which are designed to possess an intrinsic robustness against vortex-fluctuations and it provides the perspective for honorable fundamental science in condensed matter physics. Especially the nanowire detector allows for ultra-low noise detection of signals with single-photon sensitivity and GHz repetition rates. Such devices have a huge potential for future technological impact and might enable unique applications (e.g. high rate interplanetary deep-space data links from Mars to Earth).   

Holger Bartolf studied Solid State Physics at the Universities of Karlsruhe and Zürich. In 2011 he relocated at the Swiss Corporate Research Center of a leading company in power and automation technologies where his current interests focus on the applied R&D of the next generation of power semiconductors.

Autoren/Hrsg.

Bartolf, Holger

Inhaltsverzeichnis

1;Preface - Vortex-Fluctuation andSingle-Photon Detection with a Nanowire;7
1.1;Physical Background;7
1.2;Personal Remarks;9
1.3;The Scope and Organization of this Book;11
1.4;Acknowledgment, Motivation and Funding;13
1.5;References;14
2;Contents;15
3;Chapter 1 Introduction;20
3.1;1.1 Quantum Nature and its Detection;20
3.1.1;1.1.1 Thermal Detectors;21
3.1.2;1.1.2 Ionization Detectors;23
3.2;1.2 Cryogenic Quantum Detectors at the Beginning of the 21st Century;24
3.2.1;1.2.1 Transition-Edge Sensors TES;26
3.2.2;1.2.2 Kinetic-Inductance Detectors KID;27
3.2.3;1.2.3 Superconducting Tunnel Junction Detectors STJD;28
3.2.4;1.2.4 Superconducting Nanowire Single-Photon Detectors SNSPD;29
3.3;References;33
4;Part I Nanoscale Manufacturing Process Developments;41
4.1;Chapter 2 Considerations for Nanoscale Manufacturing;42
4.2;Chapter 3 Superconducting Thin-Film Preparation;44
4.2.1;3.1 DC-Magnetron Sputtering;44
4.2.1.1;3.1.1 The Physics of a DC Plasma Discharge;44
4.2.1.2;3.1.2 Magnetron Sputtering of NbN Thin Films;47
4.2.1.3;3.1.3 Magnetron Sputtering of Additional Superconducting Films;49
4.2.2;3.2 Electron-Beam Evaporation;50
4.2.3;References;51
4.3;Chapter 4 Nanoscale-Precise Coordinate System: Scalable, GDSII-Design;54
4.3.1;4.1 Process Layers;55
4.3.2;4.2 Structure References;57
4.3.3;References;59
4.4;Chapter 5 Thin-Film Structuring;60
4.4.1;5.1 Easy and Effective Nanoscaled Top-Down Manufacturing;61
4.4.2;5.2 Organic Resists;63
4.4.2.1;5.2.1 Resist Properties;63
4.4.2.2;5.2.2 Resist Fabrication: Spin Coating;64
4.4.3;5.3 Microscale Fabrication: Contact Photolithography;65
4.4.3.1;5.3.1 Principle of Photolithography;65
4.4.3.2;5.3.2 Physical Limit of Contact Photolithography;67
4.4.3.3;5.3.3 Perfect Contact Utilizing Newton’s Interference Rings;68
4.4.3.4;5.3.4 Additive and Subtractive Lithographic Pattern Transfer;70
4.4.3.5;5.3.5 Alignment Structures;73
4.4.3.6;5.3.6 Controlling the Undercut during Development;74
4.4.3.7;5.3.7 Critical Dimensions & Resist Profile;76
4.4.4;5.4 Nanoscale Fabrication: Electron-Beam Lithography;78
4.4.4.1;5.4.1 The Electron-Matter Interaction;79
4.4.4.2;5.4.2 Discrete Beam-Deflection, Exposure Dose and Dynamic Effects;82
4.4.4.3;5.4.3 Alignment of the Stage Relative to the Beam;84
4.4.4.4;5.4.4 Clearing-Dose Determination (PMMA950 k);87
4.4.4.5;5.4.5 PMMA950 k to Obtain a Lift-Off Profile: Critical Dimension 10nm;89
4.4.4.6;5.4.6 Proximity Effect Model(s);91
4.4.4.7;5.4.7 Simulated Proximity-Effect Correction;94
4.4.4.8;5.4.8 Manufacturing in the Sub - 100nm RegimeWithout Correctionfor the Proximity Effect;99
4.4.4.9;5.4.9 ZEP 520A Etch Protection Layer: Critical Dimension 60nm;102
4.4.5;5.5 Symbiotic Optimization of the Nanolithography and RF-Plasma Etching;105
4.4.6;5.6 Reactive Ion Etching;108
4.4.6.1;5.6.1 Proper Operation of the Radio-Frequency Discharge;108
4.4.6.2;5.6.2 Etching Rate Determination;111
4.4.6.3;5.6.3 Etched Photolithographic Critical Dimensions;115
4.4.7;5.7 The 50nm Scale Compared to the Bit-Pattern on a Compact-Disk;117
4.4.8;Appendix 5.1: Phenomenological Electron-Beam Proximity Effect;120
4.4.9;Appendix 5.2: CASINO: Monte Carlo Simulation of the Electron-Matter Interaction;122
4.4.10;References;123
4.5;Chapter 6 Device Manufacturing;130
4.5.1;6.1 Fabrication Process Chains;130
4.5.2;6.2 Postfabrication Procedures: Sawing & Wire Bonding;132
4.5.3;6.3 Manufacturing Twenty Devices in One Run: Small Scale Production;133
4.5.4;References;135
4.6;Chapter 7 Proof of Principle of the Above Described Approach;136
4.6.1;7.1 30nm Wide Au-Bridge;136
4.6.2;7.2 Superconducting Nb and NbN Meander;137
4.6.3;References;139
5;Part II Nanoscaled Superconductivity and its Application in Single-Photon Detectors;143
5.1;Chapter 8 Motivation for Part II;144
5.1.1;References;146
5.2;Chapter 9 Metallic and Superconducting States;147
5.2.1;9.1 Quantum Nature of the Solid State;147
5.2.2;9.2 Low-Temperature Superconductivity;150
5.2.2.1;9.2.1 Phenomenological London Theory;150
5.2.2.2;9.2.2 The Role of the Phonons:Weakly- and Strongly-Coupled Superconductors;152
5.2.2.3;9.2.3 Microscopic Bardeen-Cooper-Schrieffer (BCS) Theory;152
5.2.2.4;9.2.4 Depairing Critical Current;155
5.2.2.5;9.2.5 Phenomenological Ginzburg-Landau Theory;157
5.2.2.6;9.2.6 About Type-II Superconductivity;157
5.2.2.7;9.2.7 Ginzburg-Landau and BCS Theory (Clean- and Dirty Limit);160
5.2.3;9.3 NbN Thin Films: Extremely Dirty Type-II Superconductors;162
5.2.3.1;9.3.1 Coherence Length, Diffusivity & Resistivity;162
5.2.3.2;9.3.2 Energy Gap for Strongly-Coupled NbN;164
5.2.3.3;9.3.3 Magnetic Penetration Depth;164
5.2.3.4;9.3.4 Depairing-Critical Current in NanoscaledWires;165
5.2.3.5;9.3.5 Current-Dependence of the Energy Gap;169
5.2.4;Appendix 9.1: BCS Energy-Gap Formulæ;170
5.2.5;Appendix 9.2: Clean & Dirty Limit Expressions for theCharacteristic Length Scales of a BCS-Superconductor;174
5.2.6;Appendix 9.3: Quasiparticle Diffusivity in the Dirty Limit;181
5.2.7;Appendix 9.4: Thermodynamic Critical Field;182
5.2.8;Appendix 9.5: Depairing Critical Current Density;186
5.2.9;References;190
5.3;Chapter 10 Fluctuation Mechanisms in Superconductors;195
5.3.1;References;197
5.4;Chapter 11 Static Electronic Transport Measurements;199
5.4.1;11.1 Low Current Resistivity Measurements;199
5.4.2;11.2 Weak-Localization and Fluctuation Paraconductivity;200
5.4.3;11.3 Resistivity Measurements in a Magnetic Field;204
5.4.4;11.4 Vortex-Dissipation: BKT vs. Edge-Barrier Model;204
5.4.5;11.5 Critical-Current Measurements;211
5.4.6;11.6 Tables of Measured Sample and Material Parameters;212
5.4.7;Appendix 11.1: BKT Resistance for Finite Size Systems;217
5.4.8;References;219
5.5;Chapter 12 Theoretical Models of Current-Induced Fluctuations;223
5.5.1;12.1 Berezinskii-Kosterlitz-Thouless (BKT) Transition:Current-Assisted Thermal Unbinding of Vortex-Antivortex Pairs;223
5.5.2;12.2 Edge Barrier for Thermal and Quantum-Mechanical Vortex-Entry;225
5.5.2.1;12.2.1 Thermally-Induced Vortex Hopping;226
5.5.2.2;12.2.2 Quantum-Mechanical Vortex Tunneling;228
5.5.2.3;12.2.3 Cross-Over Temperature Tco;229
5.5.3;12.3 Thermal and Quantum Phase-Slip Mechanisms;229
5.5.4;12.4 Energy Scales for Fluctuations;231
5.5.5;12.5 Table of Calculated Model Parameters;233
5.5.6;12.6 Prediction of Fluctuation-Rates;234
5.5.7;Appendix 12.1: Minimum Energy of VAP under Bias;234
5.5.8;Appendix 12.2: Vortex-Entry Barrier Formalism;238
5.5.9;Appendix 12.3: Phase-Slip Formalism (LAMH Theory);241
5.5.10;References;250
5.6;Chapter 13Time-Resolved Photon- andFluctuation Detection;253
5.6.1;13.1 Detailed Model of the Detection Mechanism;253
5.6.2;13.2 Experimental Setup;257
5.6.2.1;13.2.1 Electronics;257
5.6.2.2;13.2.2 Single-Pulses Induced by Thermal Fluctuations;258
5.6.3;13.3 Dark Counts: Harbingers of the Current-Induced Transition into the Metallic State;261
5.6.4;13.4 Detection of Single-Photons in the400nm- 3 ?m Spectral Region;264
5.6.4.1;13.4.1 Photon Source;264
5.6.4.2;13.4.2 Analysis;265
5.6.4.3;13.4.3 Spectral Sensitivity;266
5.6.4.4;13.4.4 Count Rate at ? = 400nm;267
5.6.4.5;13.4.5 Conclusion from Photon Detection;269
5.6.5;Appendix 13.1: Single-Photon Detection by a SNSPD;269
5.6.6;References;271
5.7;Concluding Remarks and Recent Nanowire Developments;274
5.7.1;References;286
6;Fundamental Constants, Units*, Prefixes;292
7;List of Symbols;294
7.1;References;306
8;List of Abbreviations;307
9;List of Figures;310
10;List of Tables;313
11;Appendix Manufacturing Process Recipe;314
12;About the Author;327
13;Index;329