Evidence for the existence of a negatively charged hydrogen species in plasma-treated n-type Si

We demonstrate the drift of a donor-passivating hydrogen species under the action of the electric field in the depletion region of a reverse-biased Au/n-Si Schottky diode hydrogenated by exposure to a low-frequency discharge. The redistribution is explained by the unidirectional drift of a negatively charged passivating species and is confirmed by secondary-ion mass spectrometry profiling in deuterated diodes. The results are consistent with the presence of an acceptor level for hydrogen in n-type Si, and are analogous to the situation in p-type Si where drift experiments reveal the existence of positively charged hydrogen donor species.