SiGe Heterojunction Bipolar Transistors: The First Ten Years

This paper presents a review of the developments and accomplishments in SiGe Heterojunction Bipolar Transistor technology, and looks forward to the applications in the next two years, thus describing the first ten years of this new Si-based heterojunction technology. With the first report of basic HBT operation as recent as 1987, followed by a clear performance potential demonstration at the device level in 1990, and recent circuit applications and integration capability with CMOS, these events are evidence of one of the most rapid new material introductions in Si technology. The basic material effects, heterojunction operation and key leverage, and its application to bipolar transistor and circuit optimization is explained first. The technology integration and design challenges of the application to mixed signal circuitry is described next, and followed by an assessment of the potential for high speed communication circuits. It is concluded that there is a very high probability that SiGe HBT may find commercial application within 10 years after its introduction.