A transistor includes a gate structure over a substrate, wherein the substrate includes a channel region under the gate structure. The transistor further includes a source in the substrate adjacent a first side of the gate structure. The transistor further includes a drain in the substrate adjacent a second side of the gate structure, wherein the second side of the gate structure is opposite the first side of the gate structure. The transistor further includes a first lightly doped drain (LDD) region adjacent the source. The transistor further includes a second LDD region adjacent the drain. The transistor further includes a doping extension region adjacent the first LDD region.