Method and apparatus for LDMOS devices with cascaded resurf injection and double buffer

摘要

In the illustrated example, an LDMOS device (1200) is provided with at least one drift region (1222) disposed on a portion of a semiconductor substrate (1210), at least one isolation structure (1252) on the surface of the semiconductor substrate, at least one A D-well region located proximate to a portion of the two drift regions, wherein the intersection between the drift region (1222) and the D-well region is a junction (1226) between the first and second conductivity types. ) Forming a D well region, a gate structure (1282) disposed on the semiconductor substrate, a source contact region (S) disposed on the surface of the D well region, and an isolation structure (1252). Drain contact region (D) and a first buried layer (1 under the D well region and the drift region and doped to the second conductivity type) Including 28), a double buffer area including a second high voltage deep diffusion layer (1218) and which is doped to a first conductivity type located below the first buried layer.