Electrical and structural changes in GaAs crystals from high-energy, heavy-ion implants

Changes in electrical properties and crystal structure due to MeV, heavy-ion implants in GaAs have been studied. The electrical properties of the implanted samples were obtained by measuring I–V characteristic curves on and through implanted regions and Seebeck potential differences across implanted regions. The changes in crystal structure induced by the implants were measured using RBS channeling experiments and XTEM micrographs. The RBS and XTEM results indicated that MeV ion doses > 1 × 10^(15) ions/cm^2 amorphized the crystal structure at the end of ion range. After annealing the GaAs sample, the amorphized region returned to a crystalline state but with many defect centers. In n-type doped GaAs both Cl^(3+) and O^(3+) ions induced acceptor like centers which became inactive after rapid thermal annealing. Most of the active electrical carriers can be attributed to crystal defects.