In situ monitoring of hydrogen etching of Si surfaces by infrared reflection absorption spectroscopy

Etching of Si(100) and Si(111) surfaces by hydrogen atoms was investigated by BML-IRRAS. From the crystal structures, it is shown that the appearance of the SiH/sub 3/ vibration peaks indicates the occurrence of the etching (Si-Si back bond breaking) in the case of the Si(100) surface. Similarly, for the Si(111) surface, the appearances of SiH/sub 2/ and/or SiH/sub 3/ symmetric stretching and symmetric bending vibration peaks indicate the etching of Si adatoms, and the SiH/sub 2/ and SiH/sub 3/ degenerate stretching and bending vibrations indicate the etching of rest atoms. (Here the contribution of the step edges and adatom islands are ignored). Properties of these marker peaks depending on the exposure dose and temperatures are investigated here.