NATIVE OXIDE STABILIZATION OF ALAS-GAAS HETEROSTRUCTURES

Data are presented on the stabilization of AlAs-GaAs heterostructures against atmospheric (destructive) hydrolysis using the native oxide that can be formed (N2 + H2O, 400-degrees-C, 3 h) on the AlAs layer. The approximately 0.1-mu-m-thick native oxide formed from the AlAs layer is shown to be stable with aging (approximately 100 days), while unoxidized samples degrade through the AlAs (0.1-mu-m) down into the GaAs as deep as approximately 1-mu-m. Relative to oxides formed (approximately 25-degrees-C) on AlAs (or Al(x)Ga(1-x)As), x greater-than-or-similar-to 0.7) under atmospheric conditions (hydrolysis), oxides formed (via N2 + H2O) at higher temperatures (greater-than-or-similar-to 400-degrees-C) are much more stable and seal the underlying crystal (e.g., GaAs).