Kinetics of Laser-Assisted Chemical Vapor Deposition of Tungsten Microstructures

Abstract

Tungsten microstructures (dots, strips and films) have been deposited via H2 reduction of WF6 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 H2-WF6 gas mixtures and laser-induced surface temperature. At a laser-induced surface temperature ranging from 340° to 670°C with an H2 partial pressure varying from 50 to 700 Torr, the reaction order with respect to H2 was equal to one-half, whereas at higher temperatures (750°-950°C) and lower H2 partial pressures (20-80 Torr), the reaction order with respect to H2 was found to be one. The reaction mechanism of the H2 reduction of WF6 on substrates irradiated with the argon laser beam is discussed.