Thermally oxidized formation of new Ge dots over as-grown Ge dots in the Si capping layer

Thermally oxidized formation of new Ge dots over as-grown Ge dots in the Si capping layer

A Si-capped Ge quantum dot sample was self-assembly grown via Stranski-Krastanov mode in a molecular beam epitaxy system with the Si capping layer deposited at 300 C. After annealing the sample in an oxygen atmosphere at 1000 C, a structure, namely two layers of quantum dots, was formed with the newly formed Ge-rich quantum dots embedded in the oxidized matrix with the position accurately located upon the as-grown quantum dots. It has been found that the formation of such nanostructures strongly depends upon the growth temperature and oxygen atmosphere. A growth mechanism was proposed to explain the formation of the nanostructure based on the Ge diffusion from the as-grown quantum dots, Ge segregation from the growing oxide, and subsequent migration/agglomeration.

This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in J. Appl. Phys. 110, 114304 (2011) and may be found at https://doi.org/10.1063/1.3665398.