Mechanical stress caused by adsorption of O or N on a Ga-terminated (100) GaAs surface: O gives compressive stress but N don't

Effects of adsorption of O or N on a (1 /spl times/ 1)-(100) Ga-terminated GaAs were studied using small cluster models and first principle calculations. Calculation results suggest that oxidation gives compressive stress to the surface but nitridation don't. This partly explains that nitridation improves crystal disorder of oxidized GaAs. The authors calculated similar adsorption effects on InAlAs. Nitridation-after-oxidation does not realize a good interface on an InAlAs surface.