Characterization of the local structure of amorphous GaAs produced by ion implantation

The first report of the structural parameters of amorphous GaAs produced by ion implantation, as determined with extended x-ray absorption fine structure measurements, is presented herein. Relative to a crystalline sample, the nearest-neighbor bond length and Debye-Waller factor both increased for amorphized material. In contrast, the coordination numbers about both Ga and As atoms in the amorphous phase decreased to ≃3.85 atoms from the crystalline value of four. All structural parameters were independent of both implant temperature and ion dose, the latter extending two orders of magnitude beyond that required for amorphization, and as a consequence, were considered representative of intrinsic, amorphous GaAs as opposed to an implantation-induced extrinsic structure.