Preliminary results of storage accelerated aging test on InP/GaAsSb DHBT

The reliability of InP/GaAsSb/InP DHBTs designed for very high-speed ICs applications is studied after storage accelerated aging tests performed up to 2000 hours at ambient temperatures of 180, 210 and 240°C. The HiCuM model was used for modelling DC electrical characteristics measured during aging tests. The signature of the major degradation mechanism points out an evolution of the emitter access resistance. The failure mechanism is related to the Au and/or Ti diffusion into InGaAs emitter contact layer. However, the maximum current gain decrease is lower than 7% after 2000 hours at 240°C. This shows the robustness of the InP/GaAsSb/InP DHBT under test.