THERMAL-OXIDATION OF INP BI2S3 STRUCTURES IN OXYGEN/

The kinetics and mechanisms of processes involved in the thermal oxida tion of InP/Bi2S3 structures in oxygen were investigated. Surface oxid ation involves the following sequence of phase changes: bismuth sulfid e --> sulfate --> oxysulfate --> oxide. Simultaneously, reactions at t he substrate/film interface yield a dense In2S3 layer, which notably h inders diffusion of phosphorus to the surface, thus preventing its oxi dation. With increasing oxidation temperature and/or time, the indium content of the film rises. Reaction of indium with bismuth oxysulfate yields In2O3. This step, controlled by indium diffusion, provides a ma jor contribution to film growth.