Intel Corporation
Buried etch-stop layer to help control transistor source/drain depth

Abstract:

Integrated circuit structures including a buried etch-stop layer to help control transistor source/drain depth are provided herein. The buried etch-stop layer addresses the issue of the source/drain etch (or epi-undercut (EUC) etch) going below the bottom of the active height of the channel region, as such an issue can result in un-controlled sub-fin leakage that causes power consumption degradation and other undesired performance issues. The buried etch-stop layer is formed below the channel material, such as in the epitaxial stack that includes the channel material, and acts to slow the removal of material after the channel material has been removed when etching to form the source/drain trenches. In other words, the buried etch-stop layer includes different material from the channel material that can be etched, for at least one given etchant, at a relatively slower rate than the channel material to help control the source/drain trench depth.