Patent ID: 7402870
Filing Date: 2008-07-22
Classification: H01L

Abstract:
1. A field effect transistor comprising: a silicon substrate; a gate stack on a top surface of said silicon substrate; a recess in said silicon substrate at said top surface adjacent said gate stack; an epitaxial silicon halo layer in said recess on said silicon substrate; and, an epitaxial silicon source/drain layer in said recess on said epitaxial silicon halo layer, wherein said silicon substrate comprises an oxidized portion bordering said recess directly adjacent said epitaxial silicon halo layer and wherein said oxidize portion has an oxygen content below an amount which would prevent epitaxial growth of said epitaxial silicon halo layer from said oxidized portion and further above an amount required to substantially limit dopants within said epitaxial silicon halo layer and said eptiaxial silicon source/drain layer from moving into said silicon substrate.