Study of precipitate in Si-rich SiO2 films

Abstract

Silicon precipitates have been obtained in layers of Si-rich SiO 2 by ion implantation and thermal treatments. Positron annihilation spectroscopy (PAS) has been used to investigate on open volume defects existing in the oxide; other structural information has been obtained by Raman and Fourier transform infrared (FTIR) spectroscopy. Changes in positronium (Ps) formation and trapping in the implanted layer were observed. The Ps signal decreases after Ar þ ion bombardment, which induces a substantial breaking of both Si-H and Si-O bonds. Comparison with Raman measurements suggests that this effect is indirectly related to the formation of Si nano-precipitates. A strong increase of the Ps signal in the implanted samples is observed after thermal treatments at 500 and 800 8C, followed by a new decrease after a thermal treatment at 1100 8C. #

Positron annihilation on the surfaces of SiO2 films thermally grown on single crystal of Cz–Si

“…S and W parameters are defined as usual [14]. Coincidence Doppler broadening spectra were measured using a two-detector coincidence system.…”

Characterization of Implantation Induced Defects in Si-Implanted SiO2 Film

“…6 The Doppler broadening spectrum of the annihilation radiation was measured by a high-purity Ge (HPGe) detector as a function of incident positron energy E. The annihilation line was characterized by the S parameter, which gives information on positron annihilation with electrons of low and high momentum. The S parameter is defined as the ratio of the counts in the central area of the peak 511 − E ≤ 0 44 keV and the total area of the peak, here E is the energy of photon.…”

Enhancement in broadband and quasi-omnidirectional antireflection of nanopillar arrays by ion milling

“…Bulk SiO 2 has a Si-O-Si asymmetric stretching mode at 1125 cm −1 in the FTIR absorption spectrum (figure 8) [53]. This mode is sensitive to the sample stoichiometry, with a mode redshift indicating oxygen deficiency [54]. In the as-deposited SiO x NPAs, this mode appears at 1109 cm −1 , illustrating the formation of suboxides (x < 2).…”