Similarities in the electrical properties of transition metal–hydrogen complexes in silicon

We review our recent studies on the reactions of hydrogen with transition-metals (Pd, Pt, Ag, and Au) in crystalline Si. Hydrogen was incorporated into the samples by wet-chemical etching. Deep-level transient spectroscopy (DLTS) on Schottky diodes reveals several transition metal–hydrogen complexes in n- and p-type samples. From DLTS profiling, we are able to estimate the number i of hydrogen atoms in the TM–Hi complexes. All complexes with i=1, 2 are electrically active. Striking similarities are found for isoelectronic complexes, e.g. Pt–H2 and Au–H1. Transition metal complexes with more than three hydrogen atoms are likely to be electrically passive. All hydrogen related complexes disappear after heat treatments above 600 K for several hours.