A study was made of the Co-H related deep levels: Ev + 0.09eV, H(50); Ev + 0.17eV, H(90); and Ev + 0.22eV, H(150). These levels were formed by wet chemical etching or remote H plasma treatment, and annealing at 400K, in Co-doped float-zone p-type material. The H(150) level was bistable, and exhibited a fully reversible transition between an electrically active and electrically neutral configuration after zero-bias or reverse-bias annealing at temperatures of between 310 and 400K. The H(90) and H(150)

levels were tentatively attributed to a CoH complex, and the H(50) level was attributed to a CoH2 complex.

W.Jost, J.Weber, H.Lemke: Semiconductor Science and Technology, 1996, 11[4], 525-30