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

We have oxidized AlAs layers laterally in a new type of oxidation system equipped 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 fourfold increase in oxidation speed has been demonstrated with the new system. More strikingly, the saturation effect of the speed of oxidation, known to be caused by a dense As2O3-containing region at the oxidation front, appears 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-chamber 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.