The Potential of Bipolar Devices for VLSI

Most people think of MOSFET technology when they think of VLSI. Bipolar circuits are generally considered superior in performance but not competitive for VLSI applications because of their relatively large power dissipation and insufficiently dense layout. The advent of 12L/MTL nearly ten years ago brought hope that this bipolar technology, because of its very dense layout and low power dissipation, will make bipolar competitive for VLSI applications. However, it was shown that I2L/MTL in conventional bipolar technology has limited switching speeds of much greater than 2 ns even at l,um lithographic dimensions [1]. Consequently, I2L/MTL has been limited to applications where performance is not an important factor.