The surface silicon hydride composition of plasma deposited hydrogenated amorphous silicon (a-Si:H) films has been investigated through surface sensitive in situ attenuated total reflection infrared spectroscopy. The fraction of SiHx (x = 1,2,3) on the surface is reported for films deposited at substrate temperatures in the range 40-370 °C and a series decomposition reaction set in which higher hydrides decompose into lower hydrides (SiH3→SiH2→SiH) for increasing substrate temperature is proposed. Surface dangling bonds promote the decomposition reactions on a-Si:H as concluded from experiments in which the incident ion flux during deposition is enhanced. A comparison is made with results reported for hydrogenated crystalline silicon surfaces and the hydrogen coverage of the a-Si:H surface is discussed.
- Amorphous surfaces
- Infrared absorption spectroscopy
- Ion bombardment
- Plasma processing
- Surface chemical reaction