A composite etch stop layer includes an oxide layer formed over a sacrificial gate structure and a nitride layer formed over the oxide layer. The oxide layer is disposed over only lower portions of the sacrificial gate structure while the nitride layer envelops the oxide layer and is disposed directly over a top surface of the sacrificial gate structure. Sensitivity of the nitride layer to oxidation, such as during the formation of an interlayer dielectric over the composite etch stop layer, is decreased by eliminating the oxide layer from upper portions of the sacrificial gate layer.