Micro-technology relies on a highly parallel fabrication of 2D electronic and/or microelectromechanical devices, where in most cases silicon wafers are used as substrates. In contrast 3D fabrication shows unique advantages, such as footprint reduction or the possibility to obtain additional functionalities. For example, in the case of a sensor, knowledge of the acceleration in all possible directions, the surrounding electric or magnetic field among other quantities can help to determine the exact position of an object in 3D space. To do that it is crucial to retrieve all components of a vector field, which requires at least one out of plane component. In other fields like integrated optics three dimensional structures can enhance the coupling efficiency with free space interactions. As such 3D micro-structures will be crucial for upcoming products and devices. A highly parallel fabrication is required to enable mass-adaption, self-assembly is an emerging technology that could deliver this purpose. Examples of 3D structures created by self-assembly include polyhedrons like cubes, pyramids or micro tubular structures such as tubes or
spirals. Following a self assembly scheme, 3D devices would be created through the fabrication of standard 2D structures that are reshaped through a self-assembly step into a 3D object.
In this thesis a novel dry release protocol was developed to roll-up strained nanomembranes from a silicon sacrificial layer employing dry fluorine chemistry. This way a wet release is totally circumvented thus preventing damage of the created structures due to turbulent flow or capillary forces. Additionally the developed process enabled the use of standard CMOS deposition and processing tools, leading to a high increase in yield and quality, with yields exceeding 99% for microtubes. Building on the developed technology various devices where fabricated, for example rolled-up micro capacitors at a wafer scale with an increased yield and a low spread of electrical characteristics. For the E12 industrial standard more than 90% of devices behaved within the required performance characteristics. Furthermore the yield and Q-factor of roll-up whispering gallery mode resonators was strongly improved, making it possible to self assemble 3D coupled photonic molecules, which showed a mode splitting exceeding the FSR, as well as hybrid
supermodes at points of energy degeneracy.:Contents
Bibliographic Record i
List of Abbreviations vii
List of Chemical Substances ix
1 Introduction 1
1.1 Microelectromechanical Systems 1
1.2 Strain Engineering 2
1.3 Rolled - Up Nanotechnology 3
1.4 Objective and Structure of the Thesis 5
2 Materials and Methods 9
2.1 Fabrication Techniques 9
2.1.1 Substrates 9
2.1.2 Plasma Enhanced Chemical Vapor Deposition 9
2.1.3 Dry Etching12
2.1.4 Deep Reactive Ion Etching 18
2.1.5 Atomic Layer Deposition 19
2.1.6 Lithography 20
2.2 Characterization Techniques 22
2.2.1 Strain Measurement 22
2.2.2 Ellipsometry 23
3 Dry Roll-Up of Strained Nanomembranes 25
3.1 Rolled - Up Nanotechnology 25
3.2 Fabrication 26
3.2.1 Release 29
3.3 Conclusions 33
4 Rolled-UpMicro Capacitors 35
4.1 Micro Capacitors 35
4.2 Fabrication 38
4.3 Characterization 39
4.4 Conclusion 41
5 Optical Micro-Cavities 43
5.1 Optical Micro Cavities 43
5.2 Theorectical Background 45
5.2.1 Quality - factor 49
5.2.2 FDTD 52
6 Optical Microtube Resonators 55
6.1 Optical Whispering Gallery Mode Microtube Resonators 55
6.2 Fabrication 57
6.3 Active Characterization 60
6.4 Conclusions 64
7 Photonic Molecules 65
7.1 Coupled Photonic Systems 65
7.2 Fabrication 68
7.3 Device Characterization 71
7.4 Multimode Waveguides 84
7.5 Conclusions 85
8 Conclusions and Outlook 87
8.1 Conclusions 87
8.2 Outlook 88
Bibliography 91
List of Figures 109
List of Tables 117
A Equipment 119
Cover Pages 121
Selbstständigkeitserklärung 123
Acknowledgements 125
List of Publications 127
List of Presentations 129
Curriculum Vitae 131
| Identifer | oai:union.ndltd.org:DRESDEN/oai:qucosa:de:qucosa:79953 |
| Date | 24 August 2022 |
| Creators | Saggau, Christian Niclaas |
| Contributors | Schmidt, Oliver G., Fomin, Vladimir M., Technische Universität Chemnitz, IFW - Dresden |
| Source Sets | Hochschulschriftenserver (HSSS) der SLUB Dresden |
| Language | English |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, doc-type:doctoralThesis, info:eu-repo/semantics/doctoralThesis, doc-type:Text |
| Rights | info:eu-repo/semantics/openAccess |
| Relation | 10.1002/lpor.202200085, 10.1002/adma.202003252 |
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