Lateral oxidation of AlAs layers at elevated water vapour pressure using aclosed-chamber system

We have oxidized AlAs layers laterally in a new type of oxidation system eq uipped with a closed chamber, in which the vapour pressure of water can be varied over a wide range as a function of the water temperature. Up to a fo urfold increase in oxidation speed has been demonstrated with the new syste m. More strikingly, the saturation effect of the speed of oxidation, known to be caused by a dense As2O3-containing region at the oxidation front, app ears to be eventually relieved and another oxidation evolution stage begins . This observation, which we believe has been made for the first time, was possible mainly owing to the much extended oxidation time that the closed-c hamber system offers. Additionally, there is no active gas flow involved in this new oxidation method and therefore an improved spatial uniformity in oxidation is expected.