Effects of ex situ annealing on electrical characteristics of p-n-p AlGaAs/InGaAsN/GaAs double heterojunction bipolar transistors

We report the effects of postgrowth annealing on the DC characteristics of p-n-p Al_0.3Ga_0.7As/In_0.03Ga_0.97As_0.99N_0.01/GaAs (AlGaAs/InGaAsN/GaAs) double heterojunction bipolar transistors (DHBTs). The DC electrical characteristics of p-n-p AlGaAs/InGaAsN/GaAs DHBTs with postgrowth anneal are inferior to those of DHBTs without anneal. We found that the current gain decreases by a factor of two and the offset voltage and saturation voltage increase slightly, which indicate that the electrical properties of AlGaAs/InGaAsN/GaAs DHBTs could not be improved by postgrowth anneal treatment. We believe that the compensation effect on the crystalline quality of ex situ thermally annealed n-type InGaAsN base layer is the main factor for degraded DC characteristics of AlGaAs/InGaAsN/GaAs DHBTs.