ABSTRACT
The development of a bipolar technology for integrated circuits goes hand in hand with the steady improvement in semiconductor materials and discrete components during the 1950s and 1960s. Consequently, silicon bipolar technology formed the basis for the IC market during the 1970s. As circuit dimensions shrink, the MOSFET (or MOS) has gradually taken over as the major technological platform for silicon integrated circuits. The main reasons are the ease of miniaturization and high yield for MOS compared to bipolar technology. However, during the same period of MOS growth, much progress was simultaneously achieved in bipolar technology.1,2 This is illustrated in Fig. 3.1 where the reported gate delay time for emitter-coupled logic (ECL) is plotted versus year. 2,3 In 1984, the 100 ps/gate limit was broken and, since then, the speed performance has been improved by a factor of ten. The high speed and large versatility of the silicon bipolar transistor still make it an attractive choice for a variety of digital and analog applications.4
