In this thesis, a custom quadrupole mass filter setup was established to independently investigate the impact of the most prominent ion species that are present during ion-assisted deposition. The setup was applied to the low temperature epitaxial growth of GaN thin films on 6H-SiC substrates. Atomic nitrogen ions at higher ion kinetic energies were for the first time independently identified to be the predominant cause of deteriorating crystalline qualities during growth. Precise control of the ion beam parameters yielded the capability to vary the average GaN phase content from almost purely wurtzite to the meta-stable zinc blende GaN phase. Even in case of comparably high crystalline quality, the atomic and molecular nitrogen ions were independently determined to yield distinct thin film topographies throughout the entire observed evolution of the thin film formation.:Bibliographical Description
1 Introduction
1.1 Epitaxial Thin Film Growth
1.2 Ion-Beam Assisted Deposition
1.2.1 Influence of Energetic Particles
1.2.2 Ion-atom Arrival Ratio
1.3 Gallium Nitride
2 Methods
2.1 Setup of the Deposition System
2.1.1 Knudsen Effusion Cell
2.1.2 Reflection High-Energy Electron Diffraction
2.1.3 Auger Electron Spectroscopy
2.1.4 Ion Sources
2.2 Quadrupole Mass Filter System
2.2.1 Components
2.2.2 Working Principle of a Quadrupole Mass Filter
2.2.3 Alternative Mass Filters
2.3 X-ray Diffraction and Reflectivity
2.4 Atomic Force Microscopy
2.5 Transmission Electron Microscopy
3 Results and Discussions
3.1 Characterization of the Quadrupole Mass Filter System
3.1.1 Mass Filter Performance and Resolution
3.1.2 Ion Beam Characteristics
3.1.3 Space Charge Considerations
3.1.4 Conclusions
3.2 Influence of the I/A Ratio and Ion Kinetic Energy
3.2.1 Determination of the GaN Phase Composition
3.2.2 Film Topography and Growth Mode
3.2.3 Crystal Structure and Orientation
3.2.4 Microstructure at the Interface
3.2.5 Conclusions
3.3 Impact of the Ion Species on Growth Instabilities
3.3.1 Growth Rates and Thin Film Topography
3.3.2 Crystal Structure
3.3.3 Growth Mode and RHEED pattern evolution
3.3.4 Conclusions
4 Summary and Conclusions
Bibliography
Complete Publication List of the Author
Acknowledgments
Declaration of Authorship / In dieser Arbeit wurde ein maßgefertigter Quadrupol-Massenfilteraufbau etabliert, um die Auswirkungen der prominentesten Ionenspezies, die während der ionengestützten Abscheidung vorhanden sind, unabhängig voneinander zu untersuchen. Der Aufbau wurde für das epitaktische Niedertemperatur-Wachstum von GaN-Dünnschichten auf 6H-SiC-Substraten angewendet. Atomare Stickstoffionen bei höheren kinetischen Ionenenergien wurden zum ersten Mal in der Abwesenheit anderer Spezies als die dominierende Ursache für die Verschlechterung der kristallinen Qualität während des Wachstums identifiziert. Eine präzise Kontrolle der Ionenstrahlparameter ergab die Fähigkeit, den durchschnittlichen GaN-Phasengehalt von der fast reinen Wurtzit- bis zur metastabilen Zinkblende-GaN-Phase zu variieren. Selbst bei vergleichbar hoher kristalliner Qualität weisen die mit atomaren und molekularen Stickstoffionen hergestellten Schichten unabhängig voneinander verschiedene Topographien auf, die sich während der gesamten beobachteten Entwicklung der Dünnschichtbildung deutlich abzeichneten.:Bibliographical Description
1 Introduction
1.1 Epitaxial Thin Film Growth
1.2 Ion-Beam Assisted Deposition
1.2.1 Influence of Energetic Particles
1.2.2 Ion-atom Arrival Ratio
1.3 Gallium Nitride
2 Methods
2.1 Setup of the Deposition System
2.1.1 Knudsen Effusion Cell
2.1.2 Reflection High-Energy Electron Diffraction
2.1.3 Auger Electron Spectroscopy
2.1.4 Ion Sources
2.2 Quadrupole Mass Filter System
2.2.1 Components
2.2.2 Working Principle of a Quadrupole Mass Filter
2.2.3 Alternative Mass Filters
2.3 X-ray Diffraction and Reflectivity
2.4 Atomic Force Microscopy
2.5 Transmission Electron Microscopy
3 Results and Discussions
3.1 Characterization of the Quadrupole Mass Filter System
3.1.1 Mass Filter Performance and Resolution
3.1.2 Ion Beam Characteristics
3.1.3 Space Charge Considerations
3.1.4 Conclusions
3.2 Influence of the I/A Ratio and Ion Kinetic Energy
3.2.1 Determination of the GaN Phase Composition
3.2.2 Film Topography and Growth Mode
3.2.3 Crystal Structure and Orientation
3.2.4 Microstructure at the Interface
3.2.5 Conclusions
3.3 Impact of the Ion Species on Growth Instabilities
3.3.1 Growth Rates and Thin Film Topography
3.3.2 Crystal Structure
3.3.3 Growth Mode and RHEED pattern evolution
3.3.4 Conclusions
4 Summary and Conclusions
Bibliography
Complete Publication List of the Author
Acknowledgments
Declaration of Authorship
| Identifer | oai:union.ndltd.org:DRESDEN/oai:qucosa:de:qucosa:71752 |
| Date | 28 August 2020 |
| Creators | Mensing, Michael |
| Contributors | Universität Leipzig |
| 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 |
Page generated in 0.0021 seconds