ESD robust bipolar transistors with variable trigger and sustaining voltages

A new pseudo-vertical integrated npn bipolar transistor with variable sustaining and trigger voltages is presented in this paper. It is shown that the sustaining voltage can be tuned to obtain the required high value. These devices are realized in a junction isolated (JI) mixed-signal power BiCMOS technology with maximum breakdown voltage requirements in excess of 60V. The ESD robustness of these bipolar transistors is verified using transmission line pulse (TLP) and HBM (human body model) measurements. It is now possible to use a single bipolar transistor as an ESD protection device for a high voltage pin application instead of using stacked bipolar devices. The net result is a better control and possible reduction in overall die area.