A semiconductor device is provided, which includes a substrate, a first and second doped wells, a drain and source regions, a gate structure, a field plate and a booster plate. The first and second doped wells are arranged in the substrate. The drain region is arranged in the first doped well and the source region is arranged in the second doped well. The gate structure is arranged over the substrate and between the source and drain regions. The field plate is arranged over the first doped well and the booster plate arranged between the field plate and the first doped well.