48-GHz digital IC's and 85-GHz baseband amplifiers using transferred-substrate HBT's

Using substrate transfer processes, we have fabricated heterojunction bipolar transistors with submicrometer emitter-base and collector-base junctions, minimizing RC parasitics and increasing f(max) to 500 GHz, The process also provides a microstrip wiring environment on a low-epsilon(r) dielectric substrate, First design iterations of emitter-coupled-logic master-slave flip-flops exhibit 48 GHz maximum clock frequency when connected as static frequency dividers. Baseband amplifiers have been demonstrated with bandwidths up to 85 GHz.