The influence of the interface trap density on the performance of bipolar devices

The influence of the interface trap density on the DC characteristics, the AC performance, and the 1/f noise behavior of both vertical and lateral bipolar transistors of a 40-V BiCMOS process is studied. The interface trap density is changed by using different back-end process steps and is measured using the charge pumping technique. It is found that the increase of the density of interface traps result in a nonacceptable increase of the base current, even for large base-emitter voltages, and in a larger noise factor, whereas the influence on the cutoff frequency is less pronounced.<<ETX>>