Christopher Lund

Fourier transform infrared (FTIR) spectroscopy has been used to study the nature of hydrogen, oxygen and nitrogen bonds In a-Si thin films. The samples were prepared by rf sputtering under different deposition conditions to produce hydrogen contents ranging from 15 to 35 at.%. Slightly contaminated samples were found to contain nitrogen and oxygen ranging from 0.0 - 1.5 and 0.0 - 3.0 at.% respectively. Annealing vas performed by heating the samples in a hydrogen atmosphere, usually for 30 minutes, at temperatures ranging from 150 to 550 C. The FTIR spectra, taken for the as-deposited sample and after each annealing step, have been deconvoluted into their component peaks using the simplex algorithm. Our results demonstrate that for a particular type of silicon-hydrogen group, evolution of hydrogen takes place at a lower temperature from the surface and/or the near surface region than from the bulk, On the other hand, oxygen and nitrogen related bonds in the a-Si network change configurations on annealing.