Resonant-tunneling mixed-signal circuit technology

A large-scale integration (LSI) InP-based technology is described for high-speed mixed-signal circuits. The monolithic 75-mm wafer process uses molecular beam epitaxy, Inf etch stop layers, an electron-beam-defined gate, cion-alloyed ohmic contacts, and 10 mask levels to provide resonant tunneling diodes (RTD's), 0.25- or 0.5-mu m gate-length high electron mobility transistors (HEMT's), Schottky diodes, resistors, capacitors and two and a half levels of interconnect. Resonant tunneling circuits described here for the first time include a 2.5-GHz, ten stage, tapped shift register, a 6.5-GHz clock generator and a multivalued-to-binary converter. (C) 1999 Elsevier Science Ltd. All rights reserved.