Evidence of Zero Potential Spike Energy in AlGaAs/GaAs Heterostructure Emitter Bipolar Transistors

The potential spike energy at the emitter junction of AlGaAs/GaAs heterostructure emitter bipolar transistors (HEBT) was directly measured for the first time. Experimental data revealed that emitter thickness as thin as 300 Å is thick enough to eliminate potential spike without compositional grading. It is found that the band bending in n-GaAs reduces the potential spike and hence very low offset voltage of 70 mV with high current gain of 150 can be obtained.