The oxygen donor in silicon

Abstract

The effect of uniaxial stress upon the helium-like infrared absorption spectrum of the oxygen donor in Si has been examined for both the neutral and singly ionized charge states. Contrary to the well-known results for substitutional donors in Si, no splittings of the spectral features were observed for a [001] stress direction. Small splitings were observed for [110] and [111] stress directions that are a characteristic of a C 2v anisotropy. Our results are consistent with an effective-mass-like ground state wave function that is constructed from the single pair of conduction band valleys along the C 2 axis of the oxygen donor defect. Recent deep level transient spectroscopy and electron paramagnetic resonance experiments made with uniaxial stress have also been explained by a ground state wave function constructed from a single pair of conduction band valleys. The relationship between the various measurements is discussed. Outstanding problems for the oxygen donor are also described.