Abstract: The device includes a N+ buried layer in a substrate. A P-well is formed in an epitaxial layer on the buried layer. N-wells surround the P-well are also formed in the epitaxial layer. One of the N-well regions acts as a drain in the structure. A plurality of field oxide regions is formed on the N-well or P-well to define the active area of the device. A gate oxide is formed on the surface of the P-well and the N-well served as the drain. A gate is formed on the gate oxide. Drain contact is formed in the N-well for drain. The source region of the device is formed in the P-well adjacent to the drain. An isolation layer is deposited on the gate. The method includes forming a N+ buried layer in a P substrate. A P epitaxial layer is then formed on the surface of the P substrate. The N-well and P-well are respectively formed in the epitaxial layer by ion implantation and thermally diffusion. A plurality of field oxide (FOX) regions are created to define the active area.