Electrical characterisation of the p-type dopant diffusion of highly doped AlGaAs/GaAs heterojunction bipolar transistors grown by MOCVD

The emitter base threshold voltage is found to be a very efficient method of characterising p-type dopant diffusion in highly doped heterojunction bipolar transistors. Simulated curves have been successfully used to determine the amount of diffusion at different doping levels, showing the ability of MOCVD to achieve a high base doping level without any dopant diffusion.