Abstract
A thermodynamic theory of the annealing behavior of Si impurities in GaAs is presented. It is predicted that the ratio of the number of Si impurities at the Ga sites to that at the As sites is sensitive to the stress under which annealing or doping is performed. The ratio is above and below unity under a compressive stress and tensile stress exceeding a critical value, respectively. Therefore, the Si impurities act predominantly as donors and acceptors under the respective stresses. The theory is supported by our experimental finding that the Si-implanted GaAs becomes of p type by annealing under a tensile stress.