| Summary: | 碩士 === 國立成功大學 === 材料科學及工程學系 === 102 === 3C-SiC films were deposited on the (111) Si substrates by the vapor-liquid-solid (VLS) tri-phase growth method, which involved the following steps: (1) a Cu thin layer was evaporated on the Si substrate prior to the growth, (2) the substrate was heated up to melt the Cu layer, (3) methane gas (carbon source) was diffused into the liquid Cu layer to react with Si, leading to the growth of SiC films on the substrate surface. The control parameters in such a VLS growth process included growth temperature, dwelling time, Ar/CH4 ratio (i.e. carbon concentration in the ambience), and Cu layer thickness (i.e. carbon diffusion rate). These parameters controlled the nucleation process and growth rate and therefore, determined the phase purity and texture of the resultant 3C-SiC films. The optimal parameters were identified as follows: substrate temperature 1100 ℃, dwelling time 4 hour, Ar/CH4 ratio 3000/1, and Cu layer thickness 30 nm. Under such conditions, well crystallized 3C-SiC films with a preferred (111) orientation were grown. It was observed that between the grown 3C-SiC film and (111) Si substrate there was a structurally disordered transition layer of the thickness of about 1~2 nm. Such a layer was helpful to release the heteroepitaxial strain introduced by the large lattice misfit (~25%) between Si and 3C-SiC.
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