Near-ideal transport in an AlGaAs/GaAs heterostructure bipolar transistor by Na2S⋅9H2O regrowth

The deposition of sodium sulfide nonahydrate (Na2S⋅9H2O) onto mesa AlGaAs/GaAs heterostructure bipolar transistors confers near-ideal transport characteristics to the device structure. By reducing the GaAs surface recombination velocity, sulfide regrowth leads to current gain ( β) almost independent of collector current, and β>1 at collector current density below 5×10−7 A/cm−2. Furthermore, we obtain by passivation an emitter junction ideality factor of n=1.03.