Patent ID: 9502412
Filing Date: 2016-11-22
CPC Classification: H01L

Claim Text:
1. A semiconductor device structure, comprising: a substrate; a gate stack structure formed on the substrate, wherein the gate stack structure comprises a gate dielectric layer and a gate electrode layer over the gate dielectric layer; gate spacers formed on the sidewalls of the gate stack structure, wherein the gate spacers comprise a top portion and a protruding bottom portion directly below the top portion, the top portion and the protruding bottom portion form a recessed corner at a joint of the top portion and the protruding bottom portion, the recessed corner is lower than a top of the gate dielectric, and the protruding bottom portion slopes to a top surface of the substrate; and an epitaxial structure formed adjacent to the gate spacers, wherein the epitaxial structure is formed below the gate spacers.