Patent ID: 7227222

Claim:
A semiconductor device, comprising: a first conductivity type substrate having an impurity concentration; a first conductivity type first semiconductor layer formed on said substrate and having an impurity concentration lower than the impurity concentration of said substrate; a second conductivity type second semiconductor layer formed on the first semiconductor layer; an insulating film formed on said second semiconductor layer; an inductor formed on said insulating film and having a conducting film defining a width of the inductor; and a bipolar transistor and a photo diode each being formed on the substrate, wherein said first semiconductor layer and second semiconductor layer are each formed under and at least as long as the width of said inductor, wherein said photo diode has an anode and a cathode, said first semiconductor layer is comprised of one of the anode and the cathode of said photo diode, and said second semiconductor layer is comprised of another of the anode and the cathode of said photo diode.