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

Polarization-modulated infrared reflection absorption spectroscopy (aided by numerical modeling) is demonstrated as a potentially useful tool for the study of the chemistry of materials growth and processing under steady-state conditions. This approach is applied to a preliminary investigation of the growth of Cr oxide films at low-temperature (⩽270 °C) on Al 2 O 3 using Cr(CO) 6 and O 2 . The use of a buried metal layer and of polarization modulation enables detection of surface species with good sensitivity in the presence of strong absorption by gas-phase molecules. Cr(CO) 6 weakly interacting with Al 2 O 3 and Cr oxide surfaces has been observed under equilibrium conditions, and a desorption energy of ∼11 kcal/mol has been deduced from the temperature-dependent intensity of the v 6 (t 1u ) carbonyl stretching mode. The 735 cm−1 longitudinal optic mode of Cr 2 O 3 is observed during steady-state growth and simulated using the multilayer Fresnel relations for polarized reflectance. The growth is found to be first order in the Cr(CO) 6 pressure under the present conditions.