Effect of crystal stoichiometry on activation efficiency in Si implanted, rapid thermal annealed GaAs

Abstract
A dramatic dependence on crystal stoichiometry has been observed for the donor activation efficiency of low doses of Si ions implanted into undoped semi‐insulating GaAs. Samples from liquid encapsulated Czochralski crystals grown from melts containing As concentrations varying from 47 1/2 to 65 at. % were implanted with 100 keV 29Si ions at a dose of 5×1012 cm2. Following a rapid, capless annealing cycle (950 °C, 5 s), the surface‐depletion corrected activation efficiency ranged from 26 to 91%, with the higher efficiencies for higher As concentrations. In contrast, co‐implantation of As and Si into standard (50 at. % As) GaAs resulted in an increase in activation efficiency from 59 to 68% for optimum As doses.