Noise-assisted Mound Coarsening in Epitaxial Growth

TL;DR

This paper investigates how deposition noise influences unstable epitaxial growth, revealing a geometric relation among mound features and deriving scaling laws for coarsening behavior.

Contribution

It introduces the role of deposition noise in epitaxial growth and derives a geometric relation and scaling laws for mound coarsening.

Findings

The parameter R characterizes growth conditions and ranges from 0.2 to 0.7.

A scaling relation between coarsening exponent and mound height exponent is established.

For saturated mound slope, the exponents satisfy  = 1/z = 1/4.

Abstract

We propose deposition noise to be an important factor in unstable epitaxial growth of thin films. Our analysis yields a geometrical relation H=(RWL)^2 between the typical mound height W, mound size L, and the film thickness H. Simulations of realistic systems show that the parameter R is a characteristic of the growth conditions, and generally lies in the range 0.2-0.7. The constancy of R in late-stage coarsening yields a scaling relation between the coarsening exponent 1/z and the mound height exponent \beta which, in the case of saturated mound slope, gives \beta = 1/z = 1/4.