The composition of anodic oxide films on InAs crystals

Abstract

The elemental and chemical composition distribution over the indium arsenide anodic oxide films (AOF) thickness created by anodic oxidation in a galvanostatic mode at two current density values in an electrolyte containing fluoride ions are studied by X-ray photoelectron spectroscopy. The received data indicate that AOF consist of the fluoride-oxygen compounds of In and As (In and As oxyfluorides) and indium oxide (In2O3). Fluorine is accumulated near InAs-AOF boundary. Increasing of the current density from 0.05 to 0.5 mA/cm2 at constant value of both forming voltage and electrolyte composition leads to fluorine concentration near AOF-InAs boundary increasing approximately in 3 times. In turn, the forming voltage increasing at fixed current density also increases the fluorine concentration near InAs-AOF boundary but in less extent: with forming voltage increasing on 5 V more the fluorine content in the bulk AOF increases in ~1.2 and ~1.5 times at current densities of 0.05 and 0.5 mA/cm2, respectively. Thus, it is possible to change fluorine content near AOF--InAs boundary at constant fluorine-containing components concentration in initial electrolyte by varying current density and forming voltage of anodic oxidation.

Keywords

• indium arsenide, anodic oxide film, x-ray photoelectron spectroscopy, fluorine, elemental composition.