A Rutherford Backscattering Spectroscopic Study of the Aluminum Antimonide Oxidation Process in Air

The oxidation process of aluminum antimonide (AlSb) in air is investigated in detail using Rutherford backscattering spectroscopy (RBS). It is verified that AlSb is extremely liable to be oxidized by slight exposure to air. The oxidation is found to be a two-step process: an initial fast step and a subsequent slower one. In the initial step, a surface oxide with a thickness of about 150 Å is formed after AlSb is exposed to air for only a matter of minutes. This oxide gradually thickens in the subsequent step, reaching the AlSb/GaSb interface after exposure for about eighty hours. It is also clarified that the oxidized AlSb layer is amorphous and that a partly oxidized region is formed under the amorphous oxidized AlSb layer in a precursory state.