In Situ Detection of Surface SiHn in Synchrotron-Radiation-Induced Chemical Vapor Deposition of a-Si on an SiO2 Substrate

Abstract

The sensitivity and linearity of infrared reflection absorption spectroscopy (IRAS) has been significantly improved by using a buried-metal-layer (BML) substrate having an SiO(2)(15 nm)/Al(200 nm)/Si(100) structure, instead of a plain Si(100) substrate. By applying this BML-IRAS technique to the in situ observation of synchrotron-radiation-induced chemical vapor deposition of amorphous Si (a-Si) on an SiO(2) surface using Si(2)H(6) gas, the vibrational spectra of surface SiH(n) species in this reaction system have been observed for the first time with sufficient sensitivity for submonolayer coverage. The main silicon hydride species after deposition at 423 K are surface SiH(2) and SiH. Surface SiH(3) and SiH(2) are observed to be easily decomposed by synchrotron radiation irradiation. The decomposition rate of SiH by synchrotron radiation irradiation is much slower than those of SiH(2) and SiH(3).