y implanting 2.0MeV(φ= 1.0×1015/cm2)+2.9MeV(φ= 1.1 ×1015/cm2) oxygen ions into semi-insulating GaAs crystal
the sample has an almost homogeneous oxygen concentration in the range of 1.5 μm to 2.5 μm. The implanted samples were annealed respectively for 15 minutes at temperatures ranging from 400-800℃. The samples annealed at 500℃and 600℃ have high resistivity (108Ω·cm)
but those annealed at temperatures higher than 600℃ have lower resistivity and become p-type. The 2.0MeV RBS/channeling analysis shows that the crystal is almost totally recovered when annealed at temperature higher than 700℃.