Nitrogen implantation into GaP: Damage and nitrogen location studies

Implantations of 80 and 40 keV nitrogen into GaP have been carried out. The implants were performed at temperatures from 25° to 400°C for total doses in the range 1015 to 10l6 cm−2. Backscattering and channeling techniques have been used to determine the associated damage and its annealing characteristics for temperatures up to 800°C . Also determined, has been the lattice location of the implanted nitrogen. This was performed by implanting with the isotope15N and using the15N (p,αo)12C nuclear reaction in conjunction with channeling techniques using a l MeV proton beam.Results indicate that the GaP is totally damaged following 25°C implants with 1015N+cm−2. After annealing to 800°C , 70% of the damage has recovered. For implants above 100°C the initial damage is ~15%. Lattice location studies on samples implanted above 150°C show that following an 8 × 1014N+cm−2 implant, ~60% of the nitrogen is located substitutionally. The substitutional content is reduced to 33% for an 8 × 10l5N+cm-2 implant. For anneals above 600°C the nitrogen is found to move off the substitutional sites.The results show that using ion implantation at elevated temperatures it is possible to obtain high concentrations of substitutional nitrogen in relatively damage free space.