Resonant-tunneling devices and circuits

Resonant-tunneling diodes (RTDs) have demonstrated oscillation frequencies above 400 GHz and switching speeds of 2 ps, establishing them as the fastest all-electronic switches at room temperature. This high speed, together with reasonable impedance levels and straightforward integration with other III-V devices, has encouraged workers in the field to consider the potential of RTDS for selected circuit applications requiring multigigahertz speeds. Limited demonstrations have been achieved for samplers, A/D converters, parity generators, multivalued logic, and multiple-state memory. Theoretical efforts have successfully answered some of the interesting physical questions about the transient behaviour of this unique device. The author describes the process of resonant tunneling, summarizes the device and circuit achievements to date, and discusses ultimate limits and promising applications of this device.<>