Rapid Amorphization in In x Ga 1-x As Alloys at Temperatures between 15 K and 300 K

Abstract

The amorphization kinetics of In0.53Ga0.47As and In0.20Ga0.80As alloys has been investigated in comparison to its binary extremes as a function of the Ge ion fluence at room temperature and 15 K. The irradiated samples were analysed by means of Rutherford backscattering-channeling spectroscopy using an in situ technique in case of the 15 K experiments. Contrary to the AlxGa1-xAs alloys, the system InxGa1-xAs does not exhibit amorphization kinetics intermediate between those of its two binary extremes especially at room temperature. For InxGa1-xAs a smaller ion fluence is necessary to render the material amorphous at room temperature than GaAs or InAs. This surprising behaviour is explained in terms of differences in the In-As and Ga-As bond-lengths leading to strain at the atomic scale. We suggest irradiation-induced defect clusters or amorphous nuclei in InxGa 1-xAs may serve to relieve residual strain and, consequently, retardation of dynamic annealing.