Universality in Shape Evolution of Si$_{1-x}$Ge$_{x}$ Structures on High Index Silicon Surfaces

TL;DR

This paper demonstrates that Si$_{1-x}$Ge$_x$ islands grown on various high index silicon surfaces exhibit universal shape evolution and growth dynamics, explained through modified surface barrier models in simulations.

Contribution

It introduces a deviation parameter in surface barrier modeling to explain the universal shape evolution of SiGe islands across different substrate orientations.

Findings

Universality in island shape and growth exponents across substrates

Modified surface barrier model with deviation parameter explains observations

Kinematic Monte Carlo simulations support experimental results

Abstract

The MBE grown Si$_{1-x}$Ge$_x$ islands on reconstructed high index surfaces, such as, Si(5 5 12), Si(5 5 7) and Si(5 5 3) show a universality in the shape evaluation and the growth exponent parameters, \emph{irrespective} of the substrate orientations and size of the island structures. This phenomena has been explained by incorporating a deviation parameter ($\epsilon$) to the surface barrier term ($E_D$) in the kinematic Monte Carlo (kMC) simulations as one of the plausible mechanisms.