CVD kinetics of molybdenum films and simulation of the growth rate distribution in a reactor

Molybdenum films were deposited on the inner wall of a horizontal fused silica tubular reactor. Film growth rate distributions were obtained under various conditions of substrate temperature, gas flow rate and gas composition. The apparent activation energy of the film growth rate was determined as 68.5 kJ/mol between 923 and 1123 K. The apparent reaction orders and the gas flow rate dependence differed with the MoCl₅ and H₂ input gas compositions. Gas phase reaction rate proved to be relevant to these phenomena. Condensed powder from a short tube reactor was analyzed and the gas phase reaction states were analysed from the point of view of thermochemistry. A simulation model for film growth rate distributions has been proposed. It accounts for the rate of mass transfer, gas phase reaction and surface reactions. The calculated results could account for the changes in distributions with gas composition, and gas flow rate.