Characterization of Si(100) surface after high density HBr/Cl-2/O-2 plasmaetching

The nature of deposited film on unmasked Si(100) surface after high density HBr/Cl-2/O-2 plasma etching has been investigated. The as-etched surface w as treated sequentially with HF for different duration and monitored with a tomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). It was found that microscopic Si pillars are formed on the etched surface and might be attributed to the formation of micromasks. XPS surface analysis i ndicated the passivation film consists mainly of silicon oxides and oxybrom ides. Ab initio calculations using Si-4 cluster model suggested the direct attack of oxyhalide species on the surface as the energetically most favore d process. It is also shown that HF treatment for 40 s was effective in the complete removal of the residual film.