OPEN-BASE MULTI-EMITTER HBTS WITH INCREASED LOGIC FUNCTIONS

We have designed and tested a new Functional device, an open-base mult i-emitter HBT (ME-HBT) which operates at room temperature. In this pap er, we discuss the dependence of emitter doping concentration on the D C and RF characteristcs of the ME-HBTs. The collector current turn-on voltage decreases to 0.7 V with an emitter doping of 1 x 10(19) cm(-3) . A cutoff frequency of 30 GHz was obtained for the ME-HBT with an emi tter doping concentration of 1 x 10(19) cm(-3), which is the same as t hat of SEHBT on the same wafer. Using an ME-HST with an emitter doping of 3 x 10(18) cm(-3), we constructed a 3-input AND/NOR gate, and conf irmed that operation at room temperature was normal using an operating voltage of 2 V. We also discuss a problem with this ME-HBT circuit an d offer a possible solution. We believe our approach will prove useful for various ICs due to its simplicity and functionality.