OXIDATION OF SI(100)2X1 - THERMODYNAMICS OF OXYGEN INSERTION AND MIGRATION

Accurate quantum chemical calculations on model cluster molecules are used to identify and compare the most probable surface structures invo lved in the oxidation of the Si(100)2 x 1 surface. The energetics of v arious reaction channels for insertion of oxygen into Si-Si bonds are evaluated. The dimer bond is clearly shown to be the initial target of O entry and an oxygen-inserted dimer is proposed as the most likely s tructure at lower temperatures. At higher temperatures an asymmetrical ly oxidized dimer unit with three oxygen atoms inserted into Si-Si bon ds at the same silicon is the dominant feature. (C) 1997 Elsevier Scie nce B.V.