Experimental realization of the bound state resonant tunneling transistor

Abstract

Summary form only given. Bound states resonant tunneling transistors (BSRTTs) with direct contacts to ultrathin base layers ( approximately 60 AA) have been experimentally realized. In the BSRTT structure, bound states are created in the quantum well by using a base material with a low band gap. Electrons in these bound states form a low-resistance base region for application of bias to the device. Resonant tunneling of electrons via the second energy level in the well results in negative differential transconductance (NDT) or negative differential resistance (NDR) in the output current. This NDT or NDR can be used for applications in high-speed digital circuits to reduce the complexity of conventional transistor technology. The BSRTTs studied consist of a 3000-AA In/sub 0.53/Ga/sub 0.47/As emitter layer doped at 5*10/sup 18/ cm/sup -3/, an emitter stepped barrier which includes a 500-AA n/sup +/ and a 300-AA undoped In/sub 0.52/Al/sub 0.48/ layer, a 20-AA AlAs barrier, a 60-AA In/sub 0.75/Ga/sub 0.25/As base layer doped at 5*10/sup 18/ cm/sup -3/, a 20-AA AlAs barrier, a 1000-AA undoped In/sub 0.52/Al/sub 0.48/As collector barrier, and a 5000-AA In/sub 053/GA/sub 0/./sub 47/As collector layer doped at 5*10/sup 18/ cm/sup -3/. Device testing results are reported. >