Low-temperature photoluminescence techniques were used to investigate Be dopant out-diffusion from single heterojunction bipolar transistors. Near to the typical emission peak at 1.92eV, which was due to a band-to-band transition from the AlGaAs emitter, another emission peak was found in the photoluminescence spectrum. This peak was found to be caused by Be out-diffusion. The Be concentration which out-diffused into the emitter could be deduced from the energy separation between these 2 emission peaks. The results demonstrated that the low-temperature photoluminescence technique was an efficient method for identifying Be out-diffusion.

Nondestructive Determination of Beryllium Outdiffusion in AlGaAs/GaAs Heterojunction Bipolar Transistor Structures by Low-Temperature Photoluminescence H.Wang, G.I.Ng, H.Zheng, P.Zhang: Journal of Applied Physics, 1999, 86[8], 4267-72