Hydrogen molecules and hydrogen-related defects in crystalline silicon

We have found that hydrogen exists in molecular form in crystalline silicon treated with hydrogen atoms in the downstream of a hydrogen plasma. The vibrational Raman line of hydrogen molecules is observed at 4158cm^-1 for silicon samples hydrogenated between 180 and 500 ^∘{}C. The assignment of the Raman line is confirmed by its isotope shift to 2990cm^-1 for silicon treated with deuterium atoms. The Raman intensity has a maximum for hydrogenation at 400 ^∘{}C. The vibrational Raman line of the hydrogen molecules is broad and asymmetric. It consists of at least two components, possibly arising from hydrogen molecules in different occupation sites in crystalline silicon. The rotational Raman line of hydrogen molecules is observed at 590cm^-1. The Raman band of Si-H stretching is observed for hydrogenation temperatures between 100 and 500 ^∘{}C and the intensity has a maximum for hydrogenation at 250 ^∘{}C.