A New Bipolar Transistor Structure for Very High Speed VLSI

In order to develop a very high speed bipolar VLSI, several types of bipolar transistors with small parasitic elements have been developed using different kinds of self-aligned process technologies 1'2. However, these technologies are restricted to the formation of the emitter and base. Consequently, the effect of the capacitance between the collector and the substrate (CTS) upon the device performance has become more important. Moreover, transistors occupying only a small area are required to make bipolar VLSIs. For these reasons, a new bipolar structure is proposed, in which the emitter, base and collector are formed using the self-aligned process technology.