Room-temperature operation of InGaAs-based hot-electron transistors

It is demonstrated that 300-K operation of an InGaAs-based HET (hot-electron transistor) can be achieved by further increasing the electron injection energy in combination with the use of a wide-bandgap base-collector isolation barrier. The characteristics of a device consisting of an InAlAs emitter, a 10-AA AlAs tunnel-barrier positioned at the emitter-base heterojunction, a 400-AA n+ InGaAs base region, and a 2500-AA InAlGaAs collector barrier are reported. The injected electrons are transported across the base region with over 80% efficiency, as measured in a common-base configuration. The maximum common-emitter current gain in this nonoptimized transistor is nearly four with an f/sub T/ of over 40 GHz and a base-collector breakdown voltage of 1.5 V. A systematic study of RHET (resonant tunneling HET) injector and collection properties indicates that the HET can operate at room temperature with a current gain on the order of 100. 300-K operation of a single-RHET, exclusive-NOR integrated circuit that is similar in design to the one demonstrated at 77 K by N. Yokoyama et al. (1985) is also shown.