Electrical and optical characterization studies of lower dose Si-implanted AlxGa1−xN

Electrical and optical activation studies of lower dose Si-implanted AlxGa1−xN (x=0.14 and 0.24) have been made systematically as a function of ion dose and anneal temperature. Silicon ions were implanted at 200 keV with doses ranging from 1×1013 cm−2 to 1×1014 cm−2 at room temperature. The samples were proximity cap annealed from 1,100°C to 1,350°C with a 500-Å-thick AlN cap in a nitrogen environment. Nearly 100% electrical activation efficiency was obtained for Al0.24Ga0.76N implanted with a dose of 1 × 1014 cm−2 after annealing at an optimum temperature around 1,300°C, whereas for lower dose (≤5×1013 cm−2) implanted Al0.24Ga0.76N samples, the electrical activation efficiencies continue to increase with anneal temperature up through 1,350°C. Seventy-six percent electrical activation efficiency was obtained for Al0.14Ga0.86N implanted with a dose of 1 × 1014 cm−2 at an optimum anneal temperature of around 1,250°C. The highest mobilities obtained were 89 cm2/Vs and 76 cm2/Vs for the Al0.14Ga0.86N and Al0.24Ga0.76N, respectively. Consistent with the electrical results, the photoluminescence (PL) intensity of the donor-bound exciton peak increases as the anneal temperature increases from 1,100°C to 1,250°C, indicating an increased implantation damage recovery with anneal temperature.