RBS-C and ellipsometric investigations of radiation damage in hot-implanted GaAs layers

Semi-insulating (1 0 0) GaAs single crystalline substrates have been doubly Al+-implanted using ion beams of the 250 keV energy and the fluence F = 3.5 × 1016 cm−2, and 100 keV with F = 9.6 × 1015 cm−2 at six target temperatures ranging from 250 to 500 °C. The radiation damage introduced by such “hot implantation” was subsequently investigated by Rutherford Backscattering Spectrometry with Channeling (RBS-C) and Variable Angle Spectroscopic Ellipsometry (VASE) techniques. Using these experimental methods we determined a degree of lattice disorder. With the increasing implantation temperature the degree of disorder substantially decreases. No evidence of full amorphization of the implanted GaAs layers has been found in the present studies. The results of non-destructive ellipsometric characterization are in good agreement with the RBS-C investigations.