Fermi level dependent properties of hydrogen in crystalline silicon

We present the results of a (D)DLTS investigation of the dissociation of bond-centre hydrogen (H+/0) from substitutional carbon. To vary the Fermi level three different shallow dopant concentrations are used and the annealing is performed under zero and reverse bias conditions over a wide temperature range from 240 to 315 K. It is demonstrated clearly that H at the bond-centre site is not only more stable in the positive charge state than in the neutral one but also more stable in samples with low electron concentrations, as predicted by theory. A quantitative description of the dissociation mechanism is obtained.