HYDROGEN COBALT COMPLEXES IN P-TYPE SILICON

We report on three cobalt-hydrogen related deep levels H(50): E(v) + 0 .09 eV, H(90): E(V) + 0.17 eV and H(150): E(V) + 0.22 eV. The levels a re formed by wet chemical etching or remote hydrogen plasma treatment and successive annealing at 400 K in cobalt-doped float-zone p-type si licon. The level H(150) is bistable and exhibits a fully reversible tr ansition between an electrically active and an electrically neutral co nfiguration after zero-bias or reverse-bias annealing at temperatures between 310 K and 400 K. We tentatively assign H(90) and H(150) to a C oH complex and H(50) to a CoH2 complex.