Deep electron traps in n-type material, which were introduced during He- or H-plasma exposure, were studied by means of isothermal capacitance transient spectroscopy. Two electron traps, Ec - 0.51eV and Ec - 0.54eV (E2 and E4, respectively), were detected at and near to surfaces which had been treated with He plasma. These He-induced traps could be passivated by H. When the samples were treated with H2 plasma, the E2 traps were only partially active and the E4 traps were not detected because they were completely passivated by H. The density of E2 traps near to sample surfaces which had been treated with H2 plasma was strongly enhanced by applying a reverse bias at room temperature. This was due to the dissociation and removal of passivating H. On the other hand, H-passivated E4 traps were reactivated only by thermal annealing. Isochronal annealing studies of He-treated samples revealed a first-order annealing of E2 traps, with an activation energy and attempt frequency of 1.5eV and 3.2 x 1014/s, respectively. The thermal dissociation of H from E4 traps obeyed first-order kinetics, and its dissociation energy and attempt frequency were 1.65eV and 4.9 x 1013/s, respectively.

Y.Sakamoto, T.Sugino, H.Ninomiya, K.Matsuda, J.Shirafuji: Japanese Journal of Applied Physics, 1995, 34[I-10], 5499-504