Method of manufacturing VDMOS with a termination structure

摘要

Forming a semiconductor device comprises: providing a semiconductor substrate having a first major surface, and a first conductivity type; forming a first insulated gate (IG) region and a second IG region on the substrate using a first photomasking step; forming a first doped region of a second conductivity type in the substrate through a first opening between the first and second IG regions, the first doped region self aligned to the first and second IG regions; forming a second doped region of the first conductivity type within the first doped region through the first opening, the second doped region self aligned to the first and second IG regions; forming a protective layer over the substrate; selectively patterning the protective layer using a second photomasking step to form a second opening within the first opening and a third opening above the second IG region; removing a portion of the substrate through the second opening and a portion of the second IG region through the third opening to expose a conductive portion; forming an ohmic layer over the substrate; and selectively patterning the ohmic layer using a third photomasking step to form a first ohmic contact to the semiconductor substrate and a second ohmic contact to the conductive portion. Also claimed is vertical power MOSFET device. Substrate is provided without a field oxide layer. Forming the first and second IG regions comprises: forming a gate dielectric layer over the first major surface; forming a conductive layer over the gate dielectric layer; forming an interlayer dielectric over the conductive layer; forming a first photoresist layer; patterning the photoresist layer using the first photomasking step; removing portions of the interlayer dielectric and portions of the conductive layer to form first and second IG regions; insulating exposed portions of the conductive layer, where the interlayer dielectric comprises a first silicon oxide/silicon nitride/second silicon oxide structure.