Activation of the Formation of Titanium Nitride Thin Film by Chemical Vapor Deposition

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Firstly, experimental rate data on the chemical vapor deposition of boron by reduction of boron trichloride with hydrogen are analyzed. Tungsten was used as the substrate. Under surface reaction control regime, the reaction orders with respect to boron trichloride and hydrogen are one-third and one-half, respectively. By comparing these orders with those obtained from langmuir-hinshelwood type equations, the rate controlling mechanism has been suggested to be the desorption of hydrogen chloride from the substrate. Secondly, experimental rate data of chemical vapor deposition of titanium nitride from the reactant gases H_2, N_2 ant TiCl_4 were analyzed. Under surface reaction control regime, the deposition rate was in proportion to the square root of the partial pressures of hydrogen and nitrogen, respectively. The deposition rate decreased with increasing partial pressure of TiCl_4. By comparing these results with langmuir-hinshelwood type equations, it has been suggested that the probable rate-controlling step is the reaction of hydrogen atoms with nitrogen atoms on the reaction surface or the adsorption of hydrogen molecules and that of nitrogen molecules on the surface. The extent of surface coverage by these atoms is considered to have been reduced when the partial pressure of TiCl_4 is increased, due to competitive adsorption. Finally, the effects of light irradiation on the deposition rate of TiN were investigated under surface reaction control regime. The wave length of the light is 253.7 nm. The deposition rate with irradiation on the gases was smaller than that without irradiation. It is considered that TiCl_4 vapor becomes active with light irradiation and the extent of surface coverage by TiCl_4 is increased, and that by hydrogen and nitrogen which are reactants in the rate-controlling step has been reduced. When the substrate was irradiated, the activation of the formation of TiN was observed.