Recovery of crystallinity of ion implanted GaAs by short-duration laser irradiation

We have performed annealing of P+ ion implanted GaAs by means of short-duration laser irradiation less than one second. Annealing behaviors have been investigated by a micro-Raman scattering measurement as functions of the ion dose and dose rate. The short-duration annealing was successfully done on ion implanted GaAs wafers, and excellent recovery of crystallinity (∼100%) was obtained for heavily implanted GaAs. Characteristics of annealing are classified into three regions depending upon total ion dose. In the cases of low doses (≤2x1012 ions/cm2, stage I) and also high doses (1x1014 ions/cm2 ≤ oe ≤ 1x1015 ions/cm2, stage III) crystallinity recovered almost perfectly. On the other hand, in the case of intermediate region (1x1012 ions/cm2 < oe < 1x1014 ions/cm2, stage II) recovery was worse and the recovery process was somewhat complicated. We found also that the recovery of crystallinity depends on ion dose rate for the intermediate dose region. Importance of high dose rate implantation and high speed laser annealing method for GaAs is emphasized in this paper. (author)