Electrical activation and local structure of Se atoms in ion-implanted indium phosphide

The solid phase regrowth, dopant activation, and local environments of Se-implanted InP are investigated with ion-beam techniques and extended x-ray-absorption fine structure spectroscopy. We find that the local Se-In structure is already established in the as-implanted amorphous InP although the Se atoms have a lower average coordination number (similar to 3.5) and no long-range order. After high-temperature rapid thermal annealing (950 degrees C, 5 s), the amorphous InP regrows, becoming a single crystal with the Se atoms bonded to four In neighbors; however, only similar to 50% of the Se becomes electrically active. Part of the Se precipitates in the form of an In-Se phase, another part is compensated by defects which are not totally removed by annealing. The Se-In bond distance for a Se on a P site is 4.5% longer than the matrix In-P bond length, introducing large strains in the crystal. The solid solubility of Se in InP is estimated from our results to be approximate to 8.7 x 10(19)/cm(3) while the electron concentration saturates at 5.4 x 10(19)/cm(3) Se atoms in InP regrown at lower temperatures in a furnace are only similar to 7% electrically active and are found to have different local environments (higher coordination number and shorter bond distance) than those in the InP perfectly regrown at higher temperature. (C) 1996 American Institute of Physics.