CHARACTERIZATION OF THE LOCAL-STRUCTURE OF AMORPHOUS GAAS PRODUCED BYION-IMPLANTATION

The first report of the structural parameters of amorphous GaAs produc ed by ion implantation, as determined with extended x-ray absorption f ine structure measurements, is presented herein. Relative to a crystal line 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 similar to 3.85 atoms from the crystalline value of four. All structu ral parameters were independent of both implant temperature and ion do se, the latter extending two orders of magnitude beyond that required for amorphization, and as a consequence, were considered representativ e of intrinsic, amorphous GaAs as opposed to an implantation-induced e xtrinsic structure. (C) 1998 American Institute of Physics.