A device includes a semiconductor substrate and implant isolation region extending from a top surface of the semiconductor substrate into the semiconductor substrate surrounding an active region. A gate dielectric is disposed over an active region of the semiconductor substrate and extends over the implant isolation region. A gate electrode is disposed over the gate dielectric and two end cap hardmasks are between the gate dielectric and the gate electrode over the implant isolation region. The two end cap hardmasks include same dopants as those implanted into the active region.