Perturbation model for the thermal-donor energy spectrum in silicon

The general features of the repulsive potential introduced by oxygen atoms successively agglomerating around 450 degrees C thermal donors is determined by fitting the ladders of energy levels for both charge states observed by infrared spectroscopy and accounting for electron-screening effects in the neutral charge state. Recent evidence suggesting that the thermal-donor ground-state wavefunction is constructed from a pair of (100) valleys has been used to determine qualitative features of the perturbing potential. Directional agglomeration is seen to reproduce the experimental energy shifts, a result in accord with the view that thermal donors are nucleation sites for the subsequent formation of coesite.