Roughening kinetics of thin films in the presence of both stress and Ehrlich-Schwobel barrier

The growth of thin films under the interplay of shot noise, Ehrlich-Schwobel barrier (ESB), stress, and surface diffusion has been studied within a linear continuum model. It is shown that the roughening kinetics of such a system is sensitive to the growth temperature. At low temperatures, the surface growth is dominated by the ESB, while the stress controls the morphology instability at high temperatures. In the intermediate temperature regime, both the ESB effect and the stress instability become weak, thus the surface roughening is primarily driven by noise. An analysis of the film growth in this relatively stable regime reveals that at the early stages of growth the surface roughness shows an exponential dependence on the growth time, with a time-dependent growth exponent beta being larger than the value of 0.25 generated by the competition between pure noise and surface diffusion. At the late stages of growth, however, the scaling law is broken and the growth becomes unstable due to the enhanced stress and ESB effects induced by growth time. (C) 2003 American Institute of Physics.