Patent ID: 8405157

Claim:
A BiMOS semiconductor device including a semiconductor substrate which comprises in each of first and second active regions delineated by a field isolation region the following doped regions: a first doped region of a first conductivity type as a deep well, a second doped region as a doped body region of a second conductivity type that is inverse to the first conductivity type, wherein the doped body region overlaps with the deep well and has a depth from the substrate surface that is less than a depth of the deep well, and a third doped region as a depletion region of the first conductivity type, a depth thereof is less than the depth of the doped body region: wherein the first, second and third doped regions of the first active region are respectively substantially identical to said first, second and third doped regions of the second active region, and wherein a MOS transistor of the depletion type having doped source and drain regions of the first conductivity type that extend, in a depth direction, past said depletion region and into said doped body region is formed in the first active region; wherein a bipolar transistor is formed in the second active region; wherein a base of the bipolar transistor comprises said doped body region; wherein a collector of the bipolar transistor comprises said deep well; and wherein a doped emitter region of the first conductivity type and a doped base junction region of the second conductivity type are formed in said doped body region of the bipolar transistor.