Hvic device with combined level shifter and boost diode in junction termination region

A method of forming a deep buried layer for the high side of a power device comprising:

• a) forming a deep buried layer mask on the surface of a substrate doped with ions of a first conductivity type for a deep buried layer, wherein the first conductivity is opposite a second conductivity type;
• b) doping the substrate with ions of the second conductivity type through the deep buried layer mask to form a deep buried layer in the substrate;
• c) forming a first epitaxial layer on top of the substrate layer and over the deep buried layer:
• d) forming a deep well region mask over the first epitaxial layer;
• e) doping the first epitaxial layer with ions of the second conductivity type forming a deep well region;
• f) forming a second epitaxial layer over the first epitaxial layer and the deep well region;
• g) masking a surface of the second epitaxial layer with a high voltage well region mask;
• h) doping the second epitaxial layer with ions of the second conductivity through the high voltage well region mask to form a high voltage well region.