HYDROGEN-INDUCED DEFECTS IN COBALT-DOPED N-TYPE SILICON

Five new cobalt-hydrogen-related deep levels in cobalt-doped float-zon e n-type silicon are identified. The levels are formed after wet chemi cal etching, polishing or remote plasma hydrogenation. We correlate th e levels with the injection of hydrogen into cobalt-doped silicon by d eep-level transient spectroscopy (DLTS) depth profiling and capacitanc e-voltage analysis. Cleaving the sample, without any wet chemical trea tment, gives only one DLTS level, the well known Co acceptor at E(c) - 0.38 eV. The hydrogen-cobalt complexes show different thermal stabili ties. One is stable up to 470 K, but all other defects anneal out at 4 00 K and lead to an increase of the cobalt acceptor concentration.