Kinetics of the formation of titanium nitride layers by rapid thermal low pressure chemical vapor deposition from TiCl4-NH3-H2

A kinetic study of the titanium nitride growth by low pressure chemical vapor deposition (LPCVD) from gas-phase TiCl4-NH3-H-2 was carried out. Experiments were performed in the temperature range of 600-900 degrees C and in the total pressure range of 20 to 73 Pa. Partial pressures ranges were 0.4 to 2.5 Pa for TiCl4, 5 to 43 Pa for NH3, and 13 to 28 Pa for H-2. The following law of deposition was obtained r = 2.710(-5) exp (-9600/T) P-NH2(-0.63) P-TiCl4(+1.27) P-H2(0) A model was developed to explain the difference between these results and the published results, and to point out the importance of gas injection configuration on the experimental reaction orders and on the apparent activation energies. When NH3 (respectively, TiCl4) is injected quite near the substrate, this species is strongly adsorbed on the surface, and the available sites for TiCl4 adsorption (respectively, NH3) are reduced. Then the reaction order with respect to NH3 (respectively, TiCl4) is negative, and the rate-determining step is the adsorption of TiCl4 (respectively, NH3). When these two species are injected far from the substrate, the rate-determining step is the reaction between adsorbed TiCl3 and adsorbed NH or NH2.