Patent ID: 8723269

Claim:
A semiconductor device comprising: a heavily doped substrate semiconductor material of first conductivity type; and an epitaxial layer of lightly doped semiconductor material of first conductivity type formed on the heavily doped substrate material having a first impurity concentration to function as the common substrate node of a plurality of first conductivity type CMOS transistors to be built on its surface and with an epitaxial layer thickness to fully contain the subsequent formation of well regions within the epitaxial layer; and first well regions of second conductivity type formed within the epitaxial layer that have a second impurity concentration greater than the first impurity concentration of the epitaxial layer and which function as the common substrate nodes of a plurality of complementary second conductivity type CMOS transistors to be built on the surface of the first well regions and with shallow well depth that supports the integrity of each transistor and ensures full containment of the well regions within the epitaxial layer; and a thin heavily doped buried grid layer for enhanced radiation protection of second conductivity type formed within the epitaxial region extending continuously throughout the epitaxial region at a final depth such that the depth of the deepest dimension of the buried grid layer is approximate to the final depth of the first well regions to ensure electrical contact with the first well regions.