HYDROGEN MOLECULES AND HYDROGEN-RELATED DEFECTS IN CRYSTALLINE SILICON

We have found that hydrogen exists in molecular form in crystalline si licon treated with hydrogen atoms in the downstream of a hydrogen plas ma. The vibrational Raman line of hydrogen molecules is observed at 41 58 cm(-1) for silicon samples hydrogenated between 180 and 500 degrees C. The assignment of the Raman line is confirmed by its isotope shift to 2990 cm(-1) for silicon treated with deuterium atoms. The Raman in tensity has a maximum for hydrogenation at 400 degrees C. The vibratio nal Raman line of the hydrogen molecules is broad and asymmetric. It c onsists of at least two components, possibly arising from hydrogen mol ecules in different occupation sites in crystalline silicon. The rotat ional Raman lint of hydrogen molecules is observed at 590 cm(-1). The Raman band of Si-H stretching is observed for hydrogenation temperatur es between 100 and 500 degrees C and the intensity has a maximum for h ydrogenation at 250 degrees C.