Chlorine/silicon surface reactions under heating

Abstract

Reactions on Cl-adsorbed Si(111) and Si(100) surfaces—(Cl/Si(111) and Cl/Si(100))—under heating in ultrahigh vacuum (UHV) and in a Cl 2 atmosphere were studied. Auger electron spectroscopy (AES) and low-energy electron energy loss spectroscopy (LEELS) were used for examination of surface changes. Heating in UHV at 820°C for 30 s successfully removed almost all Cl atoms, both on Cl/Si(111) and Cl/Si(100). Variance in LEELS spectra shows that decomposition of SiCl x ( x > 1), a small amount of which was present on Cl/Si(111), occurs under heating on Si(111) both in UHV and in Cl 2 and desorbs reaction products, leaving the SiCl bonds on the surfaces. Such SiCl bonds specific to those on Cl/Si(111) are formed also on Cl/Si(100) heated in C1 2 at 820°C. On Cl/Si(100) heated in C1 2, there are various surface changes: relaxation of the 2 × 1 structure remaining on the Cl/Si(100), desorption of reaction products, and formation of SiCl bonds specific to those on Cl/Si(111). The SiCl bonds, both on Cl/Si(111) and Cl/Si(100), decomposed under longer heating and under heating at higher temperatures in UHV.