Device-quality a-Si:H films were prepared by glow discharge CVD with pure or H-diluted silane as well as by hot-wire CVD. The hydrogen content was varied from ∼2 to 15 at. %. The Si-H bond absorption and its light-soaking-induced changes were studied by IR and differential IR absorption spectroscopes. The results indicate that the more stable sample exhibits an increase of the absorption at wave number ∼2000 cm−1, and the less stable one exhibits a decrease at ∼2040 cm−1and an increase at ∼1880 cm−1.