KINETICS OF DISSOCIATIVE ADSORPTION OF DICHLOROSILANE ON SI(100)2X1

The temperature dependence of the dichlorosilane (SiH2Cl2) dissociativ e adsorption kinetics on a Si(100)2 x 1 surface was investigated using ultraviolet photoelectron spectroscopy (UPS). By observing in situ th e UPS intensity of the surface state originated from the dimer danglin g bonds, the time evolutions. of the surface chlorine and hydrogen cov erage during SiH2Cl2 exposure onto a Si(100) clean surface were obtain ed. They were successfully fitted with a rate equation assuming a comp etition between the SiH2Cl2 adsorption and the desorption of H-2, HCl, and SiCl. The reaction order and the reaction coefficient for the SiH 2Cl2 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 tem perature dependent partial decomposition of the adsorption precursors.