A semiconductor device includes a substrate, a gate stack, at least one epitaxy structure, a dielectric material, and a contact. The gate stack is present on the substrate. The gate spacer is present on a sidewall of the gate stack. The epitaxy structure is partially present in the substrate. The dielectric material is present on the substrate and between the epitaxy structure and the gate spacer. The contact is present on the epitaxy structure, the dielectric material, and the gate spacer.