Adsorption of TiCl4, SiH4, and HCl on Si(100): Application to TiSi2 Chemical Vapor Deposition and Si Etching

Abstract

The interactions of , , and with Si(100) have been investigated by temperature programmed desorption (TPD) with the goal of better understanding the initial stages of chemical vapor deposition for circuit metallization and wafer etching with . Coadsorption experiments with and show that under most conditions and are the main desorption products, with Ti being left behind on the surface. is a minor product. However, at sufficiently low exposures of either or , the desorption of or , respectively, is inhibited in favor of . A kinetic model involving formation of an complex at defects has been formulated which explains the results quantitatively. adsorption gives rise to the principal desorption products and , with as a minor product. The kinetic behavior can also be explained quantitatively with the proposed model. Implications for growth are discussed with reference to possible growth temperatures and source gas pressures. The mechanism for etching by is further elucidated.