Investigation of InGaP/GaAs single and double heterojunction bipolar transistors by doping spike

The InGaP/GaAs single and double heterojunction bipolar transistors (S- and D-HBT) using a doping spike of 2×10¹² cm^-2 located at heterointerfaces have been successfully fabricated with inclusion of study of potential barrier. It is found that a doping spike at emitter-base heterointerface could effectively reduce the potential barrier under forward biased condition and increase the process yield while not as to degrade the device performances. The SHBTs exhibit a common-emitter current gain as high as 410 with a very small offset voltage of 55 mV. The fabricated DHBT´s have a common-emitter current gain of 360. Further, the collector-emitter saturation (knee) voltage is lower than 2.0 V. Along with wide-gap collector and low knee voltage, the DHBTs are very promise in application to high-power system