J. Phys. IV France 02 (1991) C2-95-C2-102
THE REACTIVITY AND MOLECULAR SIZE OF FILM PRECURSORS DURING CHEMICAL VAPOR DEPOSITION OF WSixY. SHIMOGAKI, T. SAITO, F. TADOKORO and H. KOMIYAMA
Department of Chemical Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113, Japan
A kinetic study of chemical vapor deposition of tungsten silicide films was made, focusing on the reactivity and molecular size of film precursors. Tungsten silicide (WSix) films were deposited by low pressure CVD from SiH4and WF6. The molecular size of the film precursor was calculated to fit to the diffusion coefficient obtained from the deposition rate profile in a tubular reactor. Typically the size was 5~6Å, which is close to the size of the WF6 molecule. The sticking probability of the film precursor was also examined by observing step coverage in a micron size trench. The sticking probability was about 0.5 at 270~360°C and dependent only slightly on temperature. The partial pressure ratio of SiH4 to WF6 was varied from 5 to 100, but the sticking probability did not change and the step coverage remained poor. Some modifications of reaction system would be required to improve the step coverage.
© EDP Sciences 1991