Patent ID: 8178948

Claim:
An apparatus comprising: a substrate; and a plurality of unit bipolar transistors formed in the substrate, wherein each of the plurality of unit bipolar transistors includes: a first-conductivity-type buried layer formed in the substrate; a first-conductivity-type well formed over the first-conductivity-type buried layer; a second-conductivity-type well formed in the first-conductivity-type well; a first-conductivity-type vertical doping layer vertically formed from the surface of the substrate to the first-conductivity-type buried layer so as to surround the first-conductivity-type well; and a first-conductivity-type doping layer and a second conductivity-type doping layer formed in the second-conductivity-type well, and wherein the first-conductivity-type doping layer of any one of the adjacent unit bipolar transistors and the first-conductivity-type vertical doping layer of another one of the adjacent unit bipolar transistors are connected to each other.