Divacancy and resistivity profiles in n-type Si implanted with 1.15-MeV protons

Defect profiles were determined in proton-implanted low-doped ([P]=1×(Formula presented)) n-type silicon layers by performing positron-electron pair momentum-distribution measurements with a slow-positron beam, conventional positron lifetime, and (Formula presented)-(Formula presented) pair momentum-distribution measurements with a (Formula presented) and spreading resistance measurements. The dominant positron trap induced by 1.15 and 3.0 MeV proton implantations is the silicon divacancy (Formula presented). Compared to the values in bulk, the characteristic positron lifetime and the characteristic low- and high-momentum parameters of the (Formula presented)-(Formula presented) pair momentum distribution at the divacancy are (Formula presented)=300 ps=1.35(Formula presented), (Formula presented)=1.(Formula presented), and (Formula presented)=0.(Formula presented), respectively. The divacancy is observed in the negative charge state (Formula presented). The divacancy profile is determined in n-type Si implanted with 1.15-MeV (20 μm) protons to a dose 1×(Formula presented) and the maximum concentration [(Formula presented)]=4-8×(Formula presented) is observed at depths 16-18 μm. The resistivity increases with increasing divacancy concentration. After annealing at 400 °C the spreading resistance measurements reveal a region of shallow hydrogen-related donors at depths 15-21 μm. The positron annihilation results support the idea that the introduction of shallow donors is due to the formation of hydrogen-vacancy complexes during the annealing.