Current techniques for definition of the junction recess suffer from degradation of the Si crystal quality. We demonstrate the suitability of in situ chemical vapour etching (CVE) by HCl as an alternative Si etch back technique. The process has been developed in a standard epitaxial growth system and allows Si thinning without defect creation and without contamination of the remaining Si surface. In situ combination of Si etch back with facet free selective epitaxial in situ doped SiGe re-growth, makes the technique very attractive. It is a suitable technology for the fabrication of ultra-shallow source/drain junctions. The replacement of Si by SiGe might be a possible route to reduce source/drain contact resistance. (C) 2003 Elsevier B.V. All rights reserved.