US Patent 7061029 High-voltage device structure

A high-voltage device structure disposed in a substrate of a first conductivity type includes a first well and a second well each of a second conductivity type, a source diffusion region and a drain diffusion region each of a first length located in the first well and the second well respectively, and a gate of a second length on the substrate surface. Since the gate of the second length is longer than the source diffusion region and the drain diffusion region of the first length, the two sides of the gate have two spare regions. Two windows are located in the spare regions.