Abstract: In embodiments, a high voltage semiconductor device includes a gate structure disposed on a substrate, a source region disposed at a surface portion of the substrate adjacent to one side of the gate structure, a drift region disposed at a surface portion of the substrate adjacent to another side of the gate structure, a drain region disposed at a surface portion of the drift region spaced from the gate structure, and an electrode structure disposed on the drift region to generate a vertical electric field between the gate structure and the drain region.