Degradation of bipolar transistor current gain by hot holes during reverse emitter-base bias stress

Experimental evidences are given which demonstrate that degradation of the common-emitter forward current gain h_FE of submicron silicon npn bipolar transistors at low reverse emitter-base junction applied voltage is caused by primary hot holes of the n⁺ /p emitter tunneling current rather than secondary hot electrons generated by the hot holes or thermally-generated hot electrons. Experiments also showed similar kinetic energy dependence of the generation rate of oxide/silicon interface traps by primary hot electrons and primary hot holes. Significant h_FE degradation was observed at stress voltages less than 2.4 V