Dose thresholds for implantation of iron-doped indium phosphide

Silicon and beryllium ions have been implanted at 300 °K into iron doped semi-insulating InP substrates. In all cases a threshold dose was found in the high 1011 cm−2 to mid 1012 cm−2 range which depends both on the substrate and the ion being implanted. A simple model identifies the threshold fluence for n-type implantation with the excess iron in the substrate and the threshold for p-type implants with the background impurities in the substrate.