Spacer chamfering for a replacement metal gate device

摘要

Approaches for spacer chamfering in a replacement metal gate (RMG) device are provided. Specifically, a semiconductor device is provided with a set of fins formed from a substrate; a silicon-based layer conformally deposited over the set of fins; an etch-stop layer (e.g., titanium nitride (TiN)) formed over the silicon-based layer, the etch-stop layer being selective to at least one of: silicon, oxide, and nitride; a set of RMG structures formed over the substrate; a set of spacers formed along each of the set of RMG structures, wherein a vertical layer of material from each of the set of spacers is removed selective to the etch-stop layer. By chamfering each sidewall spacer, a wider area for subsequent work-function (WF) metal deposition is provided. Meanwhile, each transistor channel region is covered by the etch-stop layer (e.g., TiN), which maintains the original gate critical dimension during reactive ion etching.

主权项

1. A method for forming a semiconductor device, the method comprising:
forming a set of fins from a substrate;conformally depositing a silicon-based layer over the set of fins;forming an etch-stop layer over the silicon-based layer, the etch-stop layer having a selectivity to at least one of: silicon, oxide, and nitride;forming a set of replacement metal gate (RMG) structures over the substrate;forming a set of spacers along each of the set of RMG structures;forming a plurality of epitaxial (epi) junction areas along the set of fins between each of the set of RMG structures;depositing an oxide over the set of fins;removing a gate electrode from each of the set of RMG structures; andremoving a portion of each of the set of spacers to a top surface of the etch-stop layer.