An oxidation study of plasma-enhanced chemical vapor deposited (PECVD) and rf sputtered hydrogenated amorphous silicon carbide (a-Si1-xCx:H) films was carried out using the infrared (IR) and electron spin resonance (ESR) techniques. a-Si1-xCx:H films with x=0.3, 0.5, and 0.8 were prepared with the PECVD method and significant oxide growth can only be obtained in a-Si0.2C0.8:H film. IR results showed that Si–CH3 bonds provide the necessary porous structure for oxide growth. The oxide quality was found to be poor when compared to oxide obtained from pure silicon. Annealing in nitrogen enhances the porosity of the PECVD films and results in faster oxide growth. For sputtered films, oxide growth can only be observed in film containing Si–CH3 bonds. We are not able to separate the contributions of the Si–H, Si–C, Si–CH3, and the Si dangling bonds to the oxide growth for the PECVD and rf sputtered films. © 2001 American Institute of Physics.