Electrical Properties of Transition Metal Hydrogen Complexes in Silicon

ABSTRACTA summary is given on the electrical properties of transition-metal hydrogen complexes in silicon. Contrary to the general understanding, hydrogen leads not only to a passivation of deep defect levels but also creates several new levels in the band gap due to electrically active transition-metal complexes. We present detailed data for Pt-H complexes and summarize briefly our results on the transition metals Ti, Co, Ni, Pd, and Ag. The introduction of hydrogen at room temperature by wet chemical etching, followed by specific annealing steps allows us to study the formation of the different complexes. In particular, depth profiles of the defect concentrations give an estimate of the number of hydrogen atoms involved in the complexes. Transition-metals binding up to four hydrogen atoms are identified.