Implantation with 2MeV Si and 3MeV Zn or Ga ions, and annealing, were used to eliminate threading dislocations from 3-thick GaAs on Si. It was found that Si implantation was the most effective in reducing the number of threading dislocations, at annealing temperatures ranging from 600 to 1000C, in the near-surface region where excess vacancies were created by implantation. This suggested that the dislocations disappeared by absorbing vacancies. However, no appreciable reduction in the number of dislocations was observed in the case of Zn or Ga implantation; especially for annealing temperatures above 800C. However, at temperatures below 700C, the number of dislocations in the surface region was clearly reduced, as compared with that in a non-implanted sample. These differing effects upon the dislocation behavior were attributed to differing movements of the impurities towards the surface during annealing.

M.Tamura, T.Saitoh: Materials Science Forum, 1995, 196-201 1881-6