Characterization of Si(100) surface after high density HBr/Cl2/O2 plasma etching

Abstract

The nature of deposited film on unmasked Si(100) surface after high density HBr/Cl2/O2 plasma etching has been investigated. The as-etched surface was treated sequentially with HF for different duration and monitored with atomic 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 indicated the passivation film consists mainly of silicon oxides and oxybromides. Ab initio calculations using Si4 cluster model suggested the direct attack of oxyhalide species on the surface as the energetically most favored process. It is also shown that HF treatment for 40s was effective in the complete removal of the residual film.