Microstructural investigation of low temperature chemical vapor deposited 3C-SiC/Si thin films using single-source precursors

Transmission electron microscopy (TEM) was utilized to investigate microstr uctures of heteroepitaxial SiC/Si films, grown from single-source precursor s such as tetramethylsilane [TMS, Si(CH3)(4)], hexamethyldisilane [HMDS, Si -2(CH3)(6)], and 1,3-disilabutane [1,3-DSB, H3SiCH2SiH2CH3]. In the case of TMS/H-2 and HMDS/H-2 samples, SiC/Si films grown at relatively high precur sor concentration and/or low temperatures showed columnar grains with a hig h degree of epitaxial relationship with the Si substrate. Higher quality fi lms with larger grains were observed in the case of high temperature and/or low precursor concentration samples, although a high density of interfacia l voids was observed. Samples grown from pure 1,3-DSB at a low pressure sho wed high quality single crystalline films with few interfacial voids. It wa s suggested that the microstructural behavior of these films closely resemb les that of the SiC films formed during the carbonization of Si surfaces by the pyrolysis of hydrocarbons, in which the nucleation rate of the film at the initial stage plays a key role. The improvement achieved during the 1, 3-DSB growth is proposed to be due to the low growth pressure and the 1 : 1 ratio of Si and C associated with this precursor.