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.