A THEORETICAL-STUDY OF THE INITIAL-STAGES OF SI(111)-7X7 OXIDATION .2. THE DISSOCIATED STATE AND FORMATION OF SIO4

In a preceding paper (referred to as part I) we presented a theoretical study of the initial stages of the oxidation of the Si(111). Specifically, we discussed the structure of the molecular precursors and the stable products, using approximate molecular orbital calculations of the extended Huckel type. In this contribution (part II) we propose pathways which lead from one oxygen chemisorption configuration to another. A scheme is constructed to account for the reaction sequence from the clean Si(111) surface to molecular precursors, through dissociated states and finally to SiO4 units which are precursors for bulk-like SiO2.