ANNEALING STUDY OF THE INFRARED-ABSORPTION IN AN AMORPHOUS-SILICON DIOXIDE FILM

The temperature-dependence and annealing behavior of the IR absorption in an a-SiO2 film have been studied up to 350°C. Both reversible and irreversible effects of annealing have been observed for the O-H (s) band, with the latter effects due to the loss of hydrogen from the film. For film temperatures of 150°C and above, the O-H (s) band decreases dramatically in both area and FWHM. These changes are reversible once the film is in an anneal-stable state and are attributed to the thermally, induced breaking of hydrogen-bonded O-H...O groups. The main Si-O peak is observed to reversibly broaden and shift to lower wavenumbers for T>150°C, signaling significant changes in the local environment of the Si-O-Si bonding units at these temperatures.