US Patent 7732878 MOS devices with continuous contact etch stop layer

A semiconductor structure includes a substrate, a gate stack on the substrate, a source/drain region adjacent the gate stack, a source/drain silicide region on the source/drain region, a protection layer on the source/drain silicide region, wherein a region over the gate stack is substantially free from the protection layer, and a contact etch stop layer (CESL) having a stress over the protection layer and extending over the gate stack.