ELECTRICAL-PROPERTIES OF PLATINUM-HYDROGEN COMPLEXES IN SILICON

The interaction between hydrogen and platinum is studied in n- and p-t ype silicon using deep-level transient spectroscopy. Hydrogen is intro duced by wet-chemical etching or during crystal growth. In both cases we find that hydrogen forms only electrically active complexes with pl atinum. Four platinum-hydrogen related deep levels are identified: E(9 0) at E-C-0.18 eV, E(250) at E-C-0.50 eV, H(150) at E-V+0.30 eV, and H (210) at E-V+0.40 eV. These levels belong to at least three different platinum-hydrogen complexes. Level E(250) is identical to the so-calle d midgap level in Pt-doped Si, which is believed to control the minori ty-carrier lifetime in Pt-doped silicon. Level H(150) is an acceptor a nd is present both in n- and p-type samples after hydrogenation. It be longs to a platinum-hydrogen complex which contains more hydrogen atom s than the complexes responsible for the other hydrogen-related levels . Annealing at temperatures above 600 K results in a complete dissocia tion of all the platinum-hydrogen related defects and the substitution al platinum concentration is fully restored.