Patent ID: 6844598

Claim:
A semiconductor device, comprising: a lateral high breakdown voltage MOSFET comprising a buried layer formed in a region of a semiconductor substrate, a drain diffused layer formed on a surface side on the buried layer, a body diffused layer formed by diffusion on the surface side on the buried layer surrounding the drain diffused layer, a source diffused layer formed in the body diffused layer at a specified distance from a boundary of the drain diffused layer, a drain contact diffused layer formed on a surface side of the drain diffused layer, a gate oxide film formed on a surface of the body diffused layer, from an end of the source diffused layer over a portion of the drain diffused layer, a field oxide film formed on the surface of the drain diffused layer, in a region without the drain contact diffused layer and the gate oxide film, and a gate electrode formed above the gate oxide film over a portion of the field oxide film, wherein the gate oxide film comprises a thickness in which an electric field value of an absolute maximum rated voltage between a source and a drain is equal to or less than 4MV/cm, and a total amount of impurities in the drain diffused layer is equal to or more than 2×10 12 /cm 2 ; and a lateral low breakdown voltage MOSFET.