Si-C-H bonding in amorphous Si_1-xC_x:H film/substrate interfaces determined by real time infrared absorption during reactive magnetron sputter deposition

We determine the evolution of Si-H and C-H bonding during the growth of hydrogenated amorphous silicon carbide films by reactive magnetron sputtering of a Si target in (Ar+H₂+CH₄). Si-H and C-H modes are observed by infrared reflectance spectroscopy. An optical cavity substrate is used to enhance the sensitivity. We identify Si-H stretching modes at 2110 and 2145 cm^-1 due to Si-H clusters in microvoids and Si-H back-bonded to carbon, respectively. C-H stretching modes are identified at 2870, 2900, and 2950 cm^-1. These indicate dominant sp³ bonding configuration for C. During initial growth, a transition layer rich in H and C is observed. Steady state growth is not achieved until ≳250 Å on SiO₂ substrates, and ∼70 Å on a-Si:H substrates.