Five new Co-H related deep levels were identified in Co-doped float-zone n-type material. The levels appeared after wet chemical etching, polishing or remote plasma hydrogenation. The levels were correlated, with the injection of H into Co-doped material, by means of deep-level transient spectroscopic depth profiling and capacitance-voltage analysis. Cleaving the sample, without applying any wet chemical treatment, produced only 1 deep-level transient spectroscopic level. This was the well-known Co acceptor at Ec - 0.38eV. The H-Co complexes exhibited various thermal stabilities: one of them was stable at up to 470K, while all of the others annealed out at 400K and led to an increase in the Co acceptor concentration.

W.Jost, J.Weber, H.Lemke: Semiconductor Science and Technology, 1996, 11[1], 22-6