n -type doping characteristics of O-implanted GaN

Doping characteristics of O-implanted GaN have been investigated systematically from the viewpoint of annealing temperature. The implanted O atoms became electrically active as an n-type dopant after annealing above 1050 °C, but with a low activation efficiency of only 1.1%. From variable temperature Hall effect measurements, O-implanted GaN displayed a shallow ionization level of ∼18.3 meV after 1100 and 1200 °C anneals. In addition, secondary ion mass spectrometry measurements showed no measurable redistribution of the O atoms by the annealing. These results indicate poor probability of the O atoms occupying an N lattice site in GaN.