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 molecu lar beam epitaxy, Inf etch stop layers, an electron-beam-defined gate, cion -alloyed ohmic contacts, and 10 mask levels to provide resonant tunneling d iodes (RTD's), 0.25- or 0.5-mu m gate-length high electron mobility transis tors (HEMT's), Schottky diodes, resistors, capacitors and two and a half le vels of interconnect. Resonant tunneling circuits described here for the fi rst time include a 2.5-GHz, ten stage, tapped shift register, a 6.5-GHz clo ck generator and a multivalued-to-binary converter. (C) 1999 Elsevier Scien ce Ltd. All rights reserved.