Patent ID: 8835258
Filing Date: 2014-09-16
Classification: H01L

Abstract:
1. A manufacturing method of a high voltage device, comprising: providing a first conductive type substrate having an upper surface; forming a second conductive type buried layer in the substrate; forming a first conductive type well between the upper surface and the buried layer from cross-section view; and forming a second conductive type well beneath the upper surface, the second conductive type well having one side extending below a gate of the high voltage device and another side extending beyond a drain of the high voltage device, and the second conductive type well being connected to the first conductive type well and located at a different horizontal position from the first conductive type well, wherein the second conductive type well includes a well lower surface, which has a first part and a second part, wherein the first part is located above the buried layer and electrically coupled to the buried layer, and the second part forms a PN junction with the substrate and is not directly above the buried layer, and wherein the second conductive type well including an area beyond the drain is substantially depleted when the high voltage device operates in an OFF condition.