Microscopic structure and multiple charge states of aPtH2complex in Si

The structure and electrical properties of a ${\mathrm{PtH}}_2$ complex in Si have been studied by vibrational spectroscopy and electron paramagnetic resonance (EPR). The ${\mathrm{PtH}}_2$ complex has been found to introduce two levels in the Si band gap. One level was identified previously and lies near ${\mathit{E}}_{\mathit{c}}$-0.1 eV. A second, newly discovered level introduced by ${\mathrm{PtH}}_2$ is estimated to lie near midgap. The hydrogen vibrations of the three charge states of ${\mathrm{PtH}}_2$ have been assigned. Electron paramagnetic resonance provides detailed structural information for the paramagnetic charge state and suggests a structure with an off-center ${\mathrm{Pt}}^{\mathrm{-}}$ whose 〈001〉 distortion is reinforced by the pair of hydrogen atoms. An analysis of the small anisotropic part of the hydrogen hyperfine interaction suggests a Pt-H distance of r≊4.2 Å and helps to locate the positions of the H atoms in the complex.