Defect evolution in Co-implanted Si during annealing at 1000 °C studied using variable-energy positrons and Rutherford backscattering

Abstract

Variable-energy positron-annihilation spectroscopy ͑PAS͒ and Rutherford backscattering channeling ͑RBSC͒ have been used to probe damage induced by the implantation of n-type CzSi with Co ϩ ions at 375°C to fluences ranging from 2ϫ10 14 to 1ϫ10 16 cm Ϫ2 . For fluences of 2ϫ10 14 and 1ϫ10 15 cm Ϫ2 only one type of defect was detected using the positron technique, distributed evenly to a depth of 1 m, ϳ2.5 times that of the implanted ions. For fluences between 4ϫ10 15 and 1ϫ10 16 cm Ϫ2 a second defect type was observed, to a depth equal to the range of the implanted ions. These defects have been tentatively identified as vacancy-impurity complexes and vacancy clusters, respectively. No defects were detected using Rutherford backscattering channeling for the samples irradiated to fluences of 2ϫ10 14 and 1ϫ10 15 cm Ϫ2 ; however, defects were observed for the higher fluences. Upon annealing of the samples irradiated to these higher fluences at 1000°C for 1 min, large cavities ͑Ͼ1 nm͒ were detected using PAS. This is consistent with the dissolution of silicide precipitates previously observed using TEM. It is suggested that the formation of the cavities is dependent on the presence of vacancy clusters following the ion implantation. The evolution of the cavities at 1000°C was observed for longer annealing times. An increase in the number of extended defects was observed using RBSC following annealing to 1000°C. ͓S0163-1829͑96͒04640-1͔

Damage accumulation in Si during high-dose self-ion implantation

“…Despite these advances, it is notable that reconciliation of high temperature diffusion data with defect mobilities deduced from low temperature irradiation experiments remains an unsolved problem. [2][3][4] For most ion implantations, however, the mobilities and interactions of isolated defects are less crucial for understanding the damage state during annealing than are the properties and structures of point defect clusters. This is a consequence of most implantations being performed with heavy ions, which produce defects in high concentrations in energetic displacement cascades.…”

Positron annihilation in (Ga, Mn)N: A study of vacancy-type defects

“…19,20 Thus, in order to identify this new vacancy-type defects in ͑Ga,Mn͒N films, the W-parameter as a function of S-parameter is given in Fig. 2͑a͒.…”

Influence of intrinsic or extrinsic doping on lattice locations of carbon in semi-insulating GaN

“…S-W correlation plots are useful in detecting the change in the nature of positron trapping defects, since the slope of those plots is a fingerprint of a specific defect. 23) Thus, in order to identify newly generated V Ga -related defects after annealing, S-W correlation plots of the as-grown and annealed samples of intrinsically and extrinsically C doped GaN layers are shown in Figs. 2(a) and 2(b).…”