Chemomechanical polishing of silicon: Surface termination and mechanism of removal

Abstract

Infrared spectroscopy of Si(111) samples immediately after chemomechanical planarization with silica slurry (‘‘siton polishing’’) shows that the surfaces are predominantly terminated by hydrogen. This hydrogen termination is responsible for the observed strong hydrophobicity peak at a slurry pH of 11, at which point a monohydride termination prevails. At higher or lower pH, silanol groups replace some of the hydrogen species causing an increase in surface hydrophilicity. A removal mechanism is proposed which involves the interplay of oxidation by OH− and subsequent termination by H.