XPS Study of the Process of HgCdTe Oxidation in a Glow Discharge Oxygen Plasma

Resumo

Initial stages of HgCdTe oxidation in a glow discharge plasma in O₂ atmosphere are first studied using the XPS method. The chemical composition of the growing native oxide layer is investigated and the oxidation kinetics is revealed. It is experimentally established that the mechanism of HgCdTe oxidation changes as the oxide thickness reaches 2-3 nm due to the change of the limiting stage of the chemical reaction. The composition of the formed oxide is varies with depth and is characterized by low mercury content. It is suggested that the diffusion of oxygen to the oxide–semiconductor interface and its predominant interaction with tellurium are the main mechanism of the native MCT oxide growth, so that the oxide region bordering the substrate is ∼10% oxygen depleted. The obtained results are discussed and compared with previously reported data on MCT oxidation in RF plasma and in liquid electrolytes.