Kinetics of dissociative adsorption of dichlorosilane on Si(100)2x1

The temperature dependence of the dichlorosilane (SiH2Cl2) dissociative adsorption kinetics on a Si(100)2 x 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 SiH2Cl2 exposure onto a Si(100) clean surface were obtained. They were successfully fitted with a rate equation assuming a competition between the SiH2Cl2 adsorption and the desorption of H-2, HCl, and SiCl. The reaction order and the reaction coefficient for the SiH2Cl2 adsorption at RT were determined from the fitting to be 1.75 and 3.0 x 10(-2) ML/s, respectively, while they were changed to 1.80 and 9.0 x 10(-3) ML/s at 400 degrees C or to 3.20 and 6.0 x 10(-3) ML/s at 600 degrees C as the adsorption temperature was raised. Based on this strong temperature dependence of the parameters, we proposed a surface reaction model of the SiH2Cl2 adsorption kinetics, which includes temperature dependent partial decomposition of the adsorption precursors.