Isolation structure comprising a first doped buried layer surrounded at least in part by another doped buried layer of the same conductivity type and a trench isolation structure for an active component

Abstract

A semiconductor device comprising a substrate having a first conductivity type, the substrate having a top surface and a bottom surface, a first buried layer disposed in the substrate at a first depth from the top surface, wherein the first buried layer has a second conductivity type and a first doping concentration, a second buried layer adjacent and surrounding the first buried layer at the first depth, wherein the second buried layer has the second conductivity type and a second doping concentration, wherein the second doping concentration is less than the first doping concentration, and an isolation trench disposed in the substrate and surrounding the second buried layer, wherein the isolation trench extends from the top surface of the substrate to a second depth, the second depth exceeding the first depth.