Patent ID: 8586456

Claim:
A method of forming an epitaxial film on a substrate comprising: (a) providing a substrate; (b) exposing the substrate to a silicon source and a carbon source so as to form a carbon containing silicon epitaxial film; wherein step (b) includes: (i) exposing the substrate to the silicon source without a carbon source so as to form a first silicon epitaxial film; and (ii) exposing the substrate to the silicon source with the carbon source so as to form a carbon containing silicon epitaxial film over the first silicon epitaxial film; (c) encapsulating the carbon containing silicon epitaxial film with an adjacent encapsulating film; wherein step (c) includes: exposing the substrate to the silicon source without the carbon source so as to form a second silicon epitaxial film over the carbon containing silicon epitaxial film; and (d) exposing the substrate to Cl2 so as to etch the encapsulating film.