Dependence of burn-in effect on thermal annealing of the GaAs:C base layer in GaInP heterojunction bipolar transistors

Abstract

We investigate in situ thermal annealing of the carbon-doped GaAs base layer in GaInP/GaAs heterojunction bipolar transistors grown by metalorganic chemical vapor deposition in order to eliminate hydrogen incorporation. The influence of the anneal on the carrier transport properties and on the burn-in effect is studied. Results show that the anneal reduces the burn-in effect due to an increase in the emitter minority carrier diffusion length which is caused by passivation of H+ recombination centers in the GaInP emitter layer. However, the anneal also degrades the base minority carrier diffusion length leading to a reduction in the current gain.