Crystal orientation of polycrystalline diamond tip array

Chen, Hon-Wen James (2004). Crystal orientation of polycrystalline diamond tip array PhD Thesis, School of Engineering, The University of Queensland.

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Author Chen, Hon-Wen James
Thesis Title Crystal orientation of polycrystalline diamond tip array
School, Centre or Institute School of Engineering
Institution The University of Queensland
Publication date 2004
Thesis type PhD Thesis
Supervisor Prof. Victor Rudolph
Total pages 137
Collection year 2004
Language eng
Subjects L
290000 Engineering and Technology
670700 Industrial Chemicals and Related Products
Formatted abstract
The main topic of this study is manufacturing highly oriented CVD diamond tips on selected area of hetero-substrate. The particular focus of this work relates to the following four key technologies to achieve this special electronic device. These are (1) the technology related to diamond tip array formation process; (2) the controlled oriented crystal growth of the diamond film; (3) microstructure analysis of diamond polycrystalline grain boundaries, defects and orientation; (4) model development for diamond film texture evolution.

The films grown in this study used microwave plasma assisted chemical vapour deposition (MACVD) on a silicon substrate; the substrate was then dissolved away to reveal the surface features on the diamond film. A lithographic method was used to produce polycrystalline diamond films having highly defined surface geometry, showing an array of diamond tips for possible application as a field emitter device. Moreover, it is possible to align the crystallite direction and affect by a voltage bias to enhance the nucleation process and influence the nuclei to a preferred orientation.

This study used electron backscattering diffraction (EBSD) to identify the crystallographic character of the polycrystalline structure of diamond films. EBSD allows direct examination of the individual diamond grains, grains boundaries and the crystal orientation of each individual crystallite. As we know, the EBSD observations are the first time show the evidence of oriented diamond growth. Consequently, the method demonstrates experimentally that oriented nucleation occurs and the thin sections allow the crystal texture to be 3D reconstructed. According to the observation of the diamond film between nuclei to top area of diamond films, a model is discussed to understand the factors of texture evolution and growth mechanisms.
Keyword Crystal growth
Diamond thin films
Grain boundaries

Document type: Thesis
Collection: UQ Theses (RHD) - UQ staff and students only
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Created: Fri, 24 Aug 2007, 18:33:41 EST