SPAT studies of near-surface defects in silicon induced by BF 2+and F++B+implantation

Abstract

Slow-position annihilation technique (SPAT) has been made on silicon samples implanted with BF 2 + and F + + B + to study the irradiation defects in the thin surface layer (approximately 700 angstrom). The Doppler broadening of the annihilation (delta) -ray energy spectra measured at a number of different incident-positron energies (0 - 16 keV) was characterized by line-shape parameters 'S.' The difference between the S parameter for implanted silicon and that for unimplanted silicon provided information about the concentration and depth of the defects. The results are identical with that obtained from high resolution Rutherford backscattering and channeling technique. This investigation demonstrates that SPAT is a powerful and sensitive technique for measuring the defects distribution in semiconductors.