InGaAs/In(AlGa)As RHET's with InAs pseudomorphic base

An InGaAs/In(AlGa)As resonant-tunneling hot-electron transistor (RHET) with an INAs pseudomorphic base to increase current gain and to reduce base resistance was designed and fabricated. The conduction band discontinuity between the InAs base and the In(AlGa)As collector barrier was estimated from the thermionic current. The band discontinuity was about 0.38 eV, which agrees well with the calculated band discontinuity taking into consideration the effect of strain. The common-emitter current gain doubled and the base resistance decreased 20% compared to InGaAs-base RHETs with the same doping concentration. A current gain cutoff frequency of 65 GHz and a maximum oscillation frequency of 50 GHz at 77 K were measured.>