Abstract
The SiOH concentration profiles as a function of depth within 
films deposited from 
, and Ar containing plasmas were measured using real‐time attenuated total reflection Fourier transform infrared spectroscopy. The effective thickness approximation in conjunction with mathematical deconvolution of the temporal evolution of the spatially averaged SiOH concentration during deposition allowed the conversion of integrated SiOH absorbance to local SiOH concentration as a function of distance normal to the substrate surface. Thus, depth profiling of SiOH species in growing 
films was realized. As an example, SiOH concentration profiles in 
deposited on Si substrates cleaned with 
plasma was studied as a function of 
‐to‐
gas flow rate ratio. For the depositions performed after 
plasma cleaning, the local concentration profiles revealed strong evidence of high SiOH density at the 
interface. This method can be applied to measuring concentration depth profiles of Si‐H, Si‐F, or any other infrared active species in plasma‐deposited films in real time.