Surface Morphology Evolution of Chemical Vapor-Deposited Tungsten Films on Si(100)

Abstract

Chemical vapor deposition (CVD) is used to prepare research-grade heterostructures and to produce the majority of industrially important thin films.[1] In particular, CVD tungsten films are used for many technological applications.[2,3] In CVD an external source maintains a fixed concentration of reactant molecules at a distance above the film surface.[4] Then, gas diffusion drives the molecules through the diffusion layer[2] towards the film surface. At the film interface a reaction must occur before new material is incorporated into the solid. Kinetic studies show that two growth regimes are usually present in CVD. At a low deposition temperature (low rate, regime I) the kinetics is controlled by the surface reaction, whereas at a high temperature (high rate, regime II), mass transport of reactants to, or reaction products from, the surface is the rate-controlling step.