Multipurpose graded silicon oxynitride cap layer

Abstract

A graded cap layer that reduces the overall height of a layer stack and provides for increased process control during subsequent patterning of the layer stack, is described with a method of making the same. The graded cap layer is configured to function as a cap layer to prevent an underlying silicide layer from lifting, a barrier layer to prevent the underlying silicide layer from being oxidized during subsequent processes, a stop layer to prevent over-etching during subsequent self-aligned source (SAS) patterning processes, and/or an anti-reflective coating (ARC) to improve the resolution of subsequent patterning processes. The graded cap layer is a relatively thin layer of silicon oxynitride with varying concentrations of nitrogen. The cap layer is deposited in a single chemical vapor deposition (CVD) or plasma enhanced chemical vapor deposition (PECVD) chamber.

Dependencies are inferred from the claim text.