Proton single-event effects in high-speed polysilicon-emitter bipolar transistors

<sec>Deep-trench isolation (DTI) bipolar transistors have been increasingly adopted in high-performance, highly integrated advanced semiconductor devices due to their superior electrical characteristics and isolation capabilities. However, existing research has shown that DTI bipolar transistors exhibit a lower linear energy transfer (LET) threshold for single-event effects (SEEs) and a larger saturated cross-section than traditional structures, making the traditional rectangular parallelepiped (RPP) model unsuitable for such devices.</sec><sec>In this study, we investigate the influence of proton incidence angle on single-event effects in high-speed DTI bipolar transistors. Proton multi-angle irradiation experiments reveal that the incidence angle significantly changes the amplitude characteristics of single-event transient voltage pulses at the collector. By introducing a nested sensitive volume in TCAD numerical simulations, the sensitive region of the DTI device is accurately defined. Geant4 simulations further demonstrate that with the increase of proton incidence angle, the integral cross-section of secondary ions in the sensitive volume significantly increases, which is determined to be the primary reason for the voltage amplitudes at the collector and base increasing with augment of tilt angle. This work provides theoretical support for radiation hardening of DTI bipolar transistors against single-event effects.</sec>