Transient imposed scaling considerations in advanced narrow-emitter bipolar transistors

This paper presents a detailed two-dimensional numerical simulation study on the switch-on transient of advanced narrow-emitter bipolar transistors. Particular emphasis is placed on the effect of the "link-up" region between the extrinsic and intrinsic bases. It is shown that due to the non-uniform current distribution during the switch-on transient, the encroachment of the extrinsic base into the intrinsic base area causes much more severe degradation in the switching speed of the device than those predicted by DC or quasi-static AC analyses. The design considerations and scaling implications imposed by this transient phenomenon are discussed.