The effect of the anneal ambient on implanted GaAs and the occurrence of compensated regions in Si implants

It has been shown that the ease with which Ga can diffuse through an SiO2 film on a Si-ion-implanted sample of GaAs can be used to advantage to change the stoichiometry of the sample by annealing in an ambient consisting of H2+HCl+GaCl. The use of the same ambient with a Se-implanted sample leads to a reduction in both the mobility and the degree of activation. Both bulk and epitaxial samples which had been coated with either SiO2 or Si3N4 and implanted to 1015 cm−2 with 400-keV Si ions were found to contain compensated or p-type regions after annealing at 900 °C. A model is suggested to account for this effect.