Atomic scale monitoring for epitaxial growth process of 3C-SiC on Si

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The objective of this project is to understand the reaction processes during the epitaxial growth of 3C-SiC on Si substrates using methylsilanes as source materials in order to realize the low temperature epitaxial growth of SiC with excellent properties.In 1999, from the experiments of crystal growth by low-pressure CVD (LPCVD) and triode plasma CVD using monometylsilane (MMS) as a source gas, the epitaxial growth at 900℃ was successful by triode plasma CVD, while the epitaxial growth was successful at higher temperature than 950℃ by LPCVD.The activation energies of SiC growth were 70kcal/mol in LPCVD and 43kcal/mol in triode plasma CVD, respectively.In 2000, to investigate the growth mechanism of SiC on Si (001) surface, the initial reaction process between dimethylsilane (DMS) and Si (2×1) surface was observed in-situ using reflection high-energy electron diffraction (RHEED). By the DMS supply after raising the substrate temperature to 650-750℃, 3C-SiC spots were observed after incu … More bation time. During the incubation time, Si c(4×4) surface reconstruction was observed. The Si c(4×4) reconstruction was considered to have been a result of the carbon atoms diffused to the Si substrate from adsorbed DMS molecules. The activation energy calculated from the Arrhenius plot of the time until the Si c(4×4) structure appeared was about 16kcal/mol. It was considered that the carbon atoms adsorbed DMS molecules diffused into the Si substrate and formed Si_xC_<1-x> alloys in order to relax the lattice mismatch between Si and SiC during incubation time. The activation energy calculated from the Arrhenius plot on the initial growth rate of SiC formation was about 45kcal/mol. This energy value was close to that of hydrogen desorption from Si surface. In this temperature region, hydrogen atoms of DMS molecules adsorbed on Si surface migrated to Si dangling bonds and thereafter desorbed from Si-H bonds. The hydrogen desorption process from Si surface is considered to be rate-limiting step.Parallel to the above investigation, SiC epitaxial growth was carried out by LPCVD and triode plasma CVD using dimethylsilane as source gas. The activation energies for SiC growth were 90kcal/mol in. In the case of the SiC growth by triode plasma CVD, on the other hand, the activation energy for the epitaxial growth hardly depended on the source materials, i. e. between MMS and DMS. Less