Study of chromium oxide film growth by chemical vapor deposition using infrared reflection absorption spectroscopy

Polarization-modulated infrared reflection absorption spectroscopy (aided b y numerical modeling) is demonstrated as a potentially useful tool for the study of the chemistry of materials growth and processing under steady-stat e conditions. This approach is applied to a preliminary investigation of th e growth of Cr oxide films at low-temperature (less than or equal to 270 de greesC) on Al2O3 using Cr(CO)(6) and O-2. The use of a buried metal layer a nd of polarization modulation enables detection of surface species with goo d sensitivity in the presence of strong absorption by gas-phase molecules. Cr(CO)(6) weakly interacting with Al2O3 and Cr oxide surfaces has been obse rved under equilibrium conditions, and a desorption energy of similar to 11 kcal/mol has been deduced from the temperature-dependent intensity of the upsilon (6)(t(1u)) carbonyl stretching mode. The 735 cm(-1) longitudinal op tic mode of Cr2O3 is observed during steady-state growth and simulated usin g the multilayer Fresnel relations for polarized reflectance. The growth is found to be first order in the Cr(CO)(6) pressure under the present condit ions.