Patent ID: 8227836

Claim:
A semiconductor device including a radio frequency (RF) power amplifier comprised of a plurality of unit bipolar transistors, the semiconductor device comprising: a wiring board having a top surface and a bottom surface opposite each other; and a semiconductor chip mounted over the top surface of the wiring board, wherein the semiconductor chip includes: a plurality of first transistor formation regions each including a first number of the plurality of the unit bipolar transistors; a second transistor formation region including a second number of the plurality of the unit bipolar transistors, wherein the first number is larger than the second number, wherein each of the plurality of unit bipolar transistors is comprised of: a substrate having a top surface and a bottom surface opposite each other; a collector layer formed over the top surface of the substrate; a base layer formed over the collector layer; and an emitter layer formed over the base layer, wherein each of the collector layer, the base layer and the emitter layer is comprised of a compound semiconductor.