Four different platinum-hydrogen complexes are identified in silicon by tra
nsient capacitance spectroscopy. From deep-level depth profiling, we are ab
le to identify the number of hydrogen atoms in the defect complexes. Three
of the platinum-hydrogen complexes are electrically active, and contain one
, two, and three hydrogen atoms, respectively. A Complete electrical passiv
ation of substitutional Pt is achieved by at least four hydrogen atoms. Our
results are in agreement with experimental data on a Pt-H-2 complex and a
theoretical study on the structure and level positions of these defect comp
lexes. [S0163-1829(99)04328-3].