Patent ID: 8237223

Claim:
A semiconductor device comprising: a substrate having a first conductivity type; an epitaxial layer having a second conductivity type and disposed on the substrate; a first sinker having the second conductivity type, disposed in the epitaxial layer, extending from the substrate to an upper surface of the epitaxial layer, connected with a first interconnect, and partitioning the epitaxial layer into a first region and a second region; a transistor disposed in the first region, wherein a drain of the transistor is electrically coupled to a first rail, and a source of the transistor is electrically coupled to a second rail; and a diode unit disposed in the second region and electrically coupled to the first rail, wherein the diode unit comprising: a doped region having the first conductivity type, disposed in the epitaxial layer, connected with a second interconnect, and electrically coupled to the first rail; and a second sinker having the second conductivity type, connected with a third interconnect, and extending from the substrate to the upper surface of the epitaxial layer, wherein the substrate is connected with the second sinker, and the diode unit is electrically coupled to the first sinker through the second sinker, a voltage level of the second interconnect is higher than voltage levels of the first and the third interconnects, and the first and the third interconnects are connected with each other.