THERMAL OXIDATION AS A METHOD OF FORMATION OF NANOSCALE FUNCTIONAL FILMS ON AIIIBV SEMICONDUCTORS: CHEMOSTIMULATED INFLUENCE OF METAL OXIDES OVERVIEW

Abstract

The use of oxides as chemostimulators of AIIIBV thermal oxidation alters the mechanism of the process of thermal oxidation of semiconductors from its own to that of transit or catalytic. The mechanism of the process is determined by the chemical nature of the oxide-chemostimulator and the way it is introduced into the system (from the gas phase or deposition on the semiconductor surface). The oxides of p-metal (PbO, Sb2O3, Bi2O3), having redominantly one stable oxidation state, realize a transit mechanism of semiconductors oxidation, regardless of the way they are introduced into the system. The oxides of d-metals (MnO2, V2O5, CrO3) introduced through the gas phase act on the processes of thermal oxidation of GaAs and InP as the chemostimulator-transitors. The effect of nanosized NiO and Co3O4 layers in the processes of InP and GaAs thermal oxidation develops as a transit type, which is confi rmed by EEA values, which are of the same order of magnitude as the EEA of own oxidation of semiconductors, the consumption of oxide-chemostimulators with the passing of the process in time, a signifi cant decrease in the relative increase in fi lm thickness during the advanced stage of the process. For nanosized layers of vanadium oxide (V) the mechanism of their effect on the process of oxidation of AIIIBV is determined to a large extent by the deposition method (within the framework of one way). Thermal oxidation of AIIIBV under the infl uence of vanadium pentoxide layers deposited by soft methods implements the transit mechanism of the process, this is indicated by the expenditure of V2O5 in fi lms during thermal oxidation without subsequent regeneration. The catalytic nature of the effect of the magnetron-deposited (hard method) layers of V2O5 in the oxidation processes of InP and GaAs is confi rmed by a sharp decrease in EEA in comparison with the own oxidation of semiconductors and the independence of its value from the thickness of the deposited V2O5 layer, the cyclic regeneration of vanadium V5+ ↔ V4+, and the dynamics of the change in the relative increase in fi lm thicknesses. In this case, the processes of phosphate and arsenate formation take place at low temperatures (450-480 °C), an effective kinetic and chemical blocking of the diffusion of unoxidized indium into a fi lm occurs, and segregation of arsenic at the inner interface prevented. All of the above leads to a signifi cant improvement in the electrophysical parameters of the fi lms.

Keywords

• indium phosphide
• gallium arsenide
• thermal oxidation
• chemostimulator
• nanosized fi lms.