Capacitance-voltage and current-voltage measurements were used to study the effects of photo-cathodic H charging upon B-doped (4.5 x 1016/cm3) crystalline material. Within the first few minutes of hydrogenation, a negative charge variation occurred at the surface, due to the formation of a thin hydride-like layer. The use of H charging for extended periods of time (30h) resulted in a large increase in the reverse dark current. This effect could be completely suppressed if the electrodes were stepped to the rest-potential (0 bias) for about 1200s. The resultant current-voltage characteristics were similar to those which were found for a non-hydrogenated sample. However, the surfaces were rough and ellipsometric measurements showed that an amorphized layer was present. Secondary ion mass spectrometry measurements revealed that H (D) was also injected to depths of up to 100nm. It was concluded that an hydrogenated layer formed during electrolytic charging, due to the incorporation of a high density of H atoms within the surface region. The increase in the dark current was attributed to H-induced defects which operated as electron-hole generation centers. This layer partially dissolved when the cathodic polarization was removed (0 bias conditions) and the dark current disappeared.

P.De Mierry, A.Etcheberry, R.Rizk, P.Etchegoin, M.Aucouturier: Journal of the Electrochemical Society, 1994, 141[6], 1539-46