Optical Study of Germanium, Germanium Plus Arsenic, and Germanium Plus Gallium Implants in Gallium Arsenide

The low temperature photoluminescence (PL) properties of single implants of Germanium and dual implants of GE+Arsenic or Ge+Gallium into semi-insulating Chromium-doped Gallium Arsenide have been analyzed. Room temperature implantation was performed at 120 keV. When dual implantation was used, samples were implanted at the same dose and energy. Ion doses ranged from 1 x 10 to the 13th power to 1 x 10 to the 15th power/cm2. Samples were encapsulated with Silicon Nitride and then annealed at temperatures ranging from 700 to 950 C. Si3N4 was removed prior to PL measurements. A PL peak due to Ge-acceptors was identified. A bound exciton peak related to Ge-donors was also observed. An acceptor peak due to residual Silicon was found in all samples. The heights of the Ge-acceptor peak and exciton peak were compared to the height of the intrinsic Si-acceptor peak. The height comparison was used in an effort to find trends of Ge-acceptor and Ge-donor transitions as a function of anneal temperature and ion dose.