Positron annihilation study of defects and Si nanoprecipitation in sputter-deposited silicon oxide films

Abstract

Positron annihilation spectroscopy was conducted to study defects and Si nanoprecipitation in sputter-deposited silicon oxide films. For as-deposited SiO 0.9 and SiO 1.9 films, Doppler broadening spectra are strongly influenced by the type of paramagnetic defects ( P b or E ′). However, the disappearance of these defects after annealing at 1050 °C in a vacuum cannot account for the corresponding change of the Doppler broadening. In annealed film of SiO 1.9, positronium formation is reduced from defect-free SiO 2 because of the presence of Si precipitates; meanwhile, in annealed film of SiO 0.9 with nanocrystalline Si (nc-Si), positron annihilation with high momentum electrons is enhanced as a result of efficient positron trapping at the nc-Si surface with oxygen.