Kinetics of Laser-Assisted Chemical Vapor Deposition of Tungsten Microstructures
Résumé
Tungsten microstructures (dots, strips and films) have been deposited via H 2 reduction of WF 6 on polycrystalline silicon-coated quartz substrates irradiated with a focused cw argon laser beam. The deposition rate of W dots, deduced from α-step measurements of the height of dots, was investigated as a function of irradiation time, composition of H 2 -WF 6 gas mixtures and laser-induced surface temperature. At a laser-induced surface temperature ranging from 340° to 670°C with an H 2 partial pressure varying from 50 to 700 Torr, the reaction order with respect to H 2 was equal to one-half, whereas at higher temperatures (750°-950°C) and lower H 2 partial pressures (20-80 Torr), the reaction order with respect to H 2 was found to be one. The reaction mechanism of the H 2 reduction of WF 6 on substrates irradiated with the argon laser beam is discussed.