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

A method of manufacturing a semiconductor device, comprising:

• providing a substrate having a first conductivity type, the substrate having a top surface and a bottom surface;
• providing a first buried layer 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;
• providing 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
• providing an isolation trench in the substrate 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, wherein the second buried layer is configured such that a breakdown region is spaced apart from the isolation trench such that the isolation trench is not in direct contact with the breakdown region and the breakdown region is located proximate a junction between the first buried layer and the second buried layer.

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, wherein the first and second buried layers have the same height;
• 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.