Kinetics of dissociative adsorption of dichlorosilane on Si(100)2 × 1

Abstract

The temperature dependence of the dichlorosilane (SiH 2Cl 2) dissociative adsorption kinetics on a Si(100)2 × 1 surface was investigated using ultraviolet photoelectron spectroscopy (UPS). By observing in situ the UPS intensity of the surface state originated from the dimer dangling bonds, the time evolutions of the surface chlorine and hydrogen coverage during SiH 2Cl 2 exposure onto a Si(100) clean surface were obtained. They were successfully fitted with a rate equation assuming a competition between the SiH 2Cl 2 adsorption and the desorption of H 2, HCl, and SiCl. The reaction order and the reaction coefficient for the SiH 2Cl 2 adsorption at RT were determined from the fitting to be 1.75 and 3.0 × 10 −2 ML/s, respectively, while they were changed to 1.80 and 9.0 × 10 −3 ML/s at 400°C or to 3.20 and 6.0 × 10 −3 ML/s at 600°C as the adsorption temperature was raised. Based on this strong temperature dependence of the parameters, we proposed a surface reaction model of the SiH 2Cl 2 adsorption kinetics, which includes temperature dependent partial decomposition of the adsorption precursors.