Self-limiting adsorption of thermally cracked SiCl2H2 on Si surfaces

We proposed SiCl2 as a new precursor for Si atomic layer epitaxy (ALE). SiCl2 was produced by thermal cracking of dichlorosilane (SiCl2H2, DCS). A cracking efficiency of 70% was obtained at a cracking temperature of 800°C. The sticking coefficient of SiCl2 on Si surfaces was found to be 103 times larger than that of DCS. Based on temperature programmed desorption and Auger electron spectroscopy measurements, it was considered that SiCl2 dissociatively adsorbed to form a fully Cl-terminated surface. The results indicated that SiCl2 produced by DCS cracking is a favorable source for Si ALE due to its high sticking probability and self-limiting adsorption properties.