Composition of the surface layer of GaAs after laser annealing of the Al-GaAs system

Laser assisted doping of GaAs from an Al thin film, deposited on its surface, has been carried out. The unreacted aluminum, left on the irradiated surface, has been removed chemically after the irradiation and the surface of the substrate has been investigated by electron microscope and X-ray diffraction studies. It has been found that when the system Al-GaAs is irradiated with lower laser energy densities, the composition of the solid phase is in the private triangle Al-GaAs-AlAs. When the system Al-GaAs is irradiated with intermediate laser energy densities, the solid phase, which probably consists of GaxAl1-xAs, has been found. When the system Al-GaAs is irradiated with high laser energy density small amounts of GaxAl1-xAs are formed in the solid phase. The results are explained on the basis of the thermal annealing model for interaction of laser irradiation with the matter. (C) 2001 Elsevier Science B.V. All rights reserved.