Precursors for Si atomic layer epitaxy: Real time adsorption studies on Si(100)

Adsorption of SiClH3 and SiCl2H2 on Si(100) is studied as a function of surface temperature, comparing these precursors for Si atomic layer epitaxy (ALE). At 450-550°C, a substantial surface H coverage (θH) exists during SiClH3 adsorption, and θH exhibits transient behavior. During SiCl2H2 adsorption, θH is much smaller. At 500°C with SiCl2H2, ≅1 monolayer of Cl is formed after ≅4×1019 cm-2 exposure. Dichlorosilane is a suitable precursor for Si ALE, but desorption of HCl is significant at T≳500°C so that SiCl2H2 adsorption is not strictly self-limiting.