IN-SITU DETECTION OF SURFACE SIHN IN SYNCHROTRON-RADIATION-INDUCED CHEMICAL-VAPOR-DEPOSITION OF A-SI ON AN SIO2 SUBSTRATE

The sensitivity and linearity of infrared reflection absorption spectroscopy (IRAS) has been significantly improved by using a buried-metal-layer (BML) substrate having an SiO2(15nm)/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 SiO2 surface using Si2H6 gas, the vibrational spectra of surface SiHn 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 SiH2 and SiH. Surface SiH3 and SiH2 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 SiH2 and SiH3.