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-degrees-C, a substantial surface H coverage (theta(H)) exists during SiClH3 adsorption, and theta(H) exhibits transient behavior. During SiCl2H2 adsorption, theta(H) is much smaller. At 500-degrees-C with SiCl2H2, congruent-to 1 monolayer of Cl is formed after congruent-to 4 X 10(19) cm-2 exposure. Dichlorosilane is a suitable precursor for Si ALE, but desorption of HCl is significant at T > 500-degrees-C so that SiCl2H2 adsorption is not strictly self-limiting.