Guarding ring structure of a high voltage device and manufacturing method thereof

Abstract

The present invention provides a guarding ring structure of a semiconductor high voltage device and the manufacturing method thereof. The guarding ring structure comprises a first N type monocrystalline silicon substrate (), a second N type monocrystalline silicon substrate (), a discontinuous oxide layer (), a metal field plate (), a device region (), multiple P+ type diffusion rings () and an equipotential ring (). The second N type monocrystalline silicon substrate () is a single N type crystalline layer epitaxially formed on the first N type monocrystalline silicon substrate () and has lower doping concentration than the first N type monocrystalline silicon substrate (). N type diffusion rings () are embedded in the inner side of the P+ type diffusion rings () and are fully depleted at zero bias voltage. The guarding ring structure can achieve the same withstand voltage with less area and design time.