A method of semiconductor fabrication includes forming a dielectric layer over a substrate. A dummy gate structure is formed on the dielectric layer, which defines a dummy gate dielectric region. A portion of the dielectric layer not included in the dummy gate dielectric region is etched to form a dielectric etch back region. A spacer element is formed on a portion of the dielectric etch back region, which abuts the dummy gate structure, and defines a spacer dielectric region A height of the dummy gate dielectric region is greater than the height of the spacer dielectric region. A recessed portion is formed in the substrate, over which a strained material is selectively grown to form a strained recessed region adjacent the spacer dielectric region. The dummy gate structure and the dummy gate dielectric region are removed. A gate electrode layer and a gate dielectric layer are formed.