High-speed InP/InGaAs DHBTs with a thin pseudomorphic base

We describe thin collector InP-based double heterojunction bipolar transistors with a thin pseudomorphic base for achieving high f/sub T/ and f/sub max/. Over-300-GHz f/sub T/ and f/sub max/ are obtained with high uniformity across a 3-inch wafer. We demonstrate an ECL gate delay of 3.48 ps/stage in a 19-stage ring-oscillator using the technology. To our knowledge, this is the first report of sub-4-ps ECL gate delay, Moreover, a record f/sub max/ in mesa HBTs of 492 GHz is also demonstrated by a further lateral scaling of DHBTs.