HVNMOS structure for reducing on-resistance and preventing BJT triggering

摘要

A high-voltage metal-oxide-semiconductor (HVMOS) device and methods for forming the same are provided. The HVMOS device includes a substrate; a first high-voltage n-well (HVNW) region buried in the substrate; a p-type buried layer (PBL) horizontally adjoining the first HVNW region; a second HVNW region on the first HVNW region; a high-voltage p-well (HVPW) region over the PBL; an insulating region at a top surface of the second HVNW region; a gate dielectric extending from over the HVPW region to over the second HVNW region, wherein the gate dielectric has a portion over the insulating region; and a gate electrode on the gate dielectric.