Zinc and phosphorus co-implantation in indium phosphide

Electrical activation and dopant diffusion in Zn-implanted InP after rapid thermal annealing have been investigated. For an as-implanted Zn concentration of ∼4×10¹⁹cm^-3, only ∼7% of the implanted Zn atoms formed electrically active shallow acceptors following a 950 °C/5 s annealing cycle. The low activation was the result of rapid Zn out-diffusion - only ∼14% of the implanted dopant was retained after annealing. A significant enhancement in electrical activation and a reduction in Zn loss were achieved in Zn+P co-implanted samples which yielded a net hole concentration of ≤6×10¹⁸cm^-3 and >50% Zn retention. The saturation of the free hole concentration in Zn+P co-implanted samples was attributed to the formation of Zn interstitial donors and Group-V-related donor-type native defects. For comparison, Zn+Al and Zn+Al+P co-implanted samples were also examined to distinguish the relative influences of implantation-induced disorder and nonstoichiometry on electrical activation and dopant diffusion. For the given implant conditions, we found that nonstoichiometry was the dominant influence.