Methods for forming structures that include forming a heteroepitaxial layer on a substrate are disclosed. The presently disclosed methods comprise epitaxially forming a buffer layer on the substrate. The substrate has a substrate composition. The buffer layer has a buffer layer composition. The buffer layer composition is substantially identical to the substrate composition. The presently disclosed methods further comprise epitaxially forming a heteroepitaxial layer on the buffer layer. The heteroepitaxial layer has a heteroepitaxial layer composition which is different from the substrate composition.

Exemplary semiconductor processing methods may include forming a barrier layer on a first source/drain material disposed on a substrate housed within a processing region of a semiconductor processing chamber. The first source/drain material may be doped with a dopant. The methods may include growing an epitaxial silicon-containing material on the barrier layer. The barrier layer may reduce an amount of diffusion of the dopant from the first source/drain material into the epitaxial silicon-containing material.