Low-voltage triggering SCRs for ESD protection in a 0.35 μm SiGe BiCMOS process

A heterojunction bipolar transistor (HBT) trigger Silicon Controlled Rectifier (SCR) device (HTSCR) in the 0.35 μm Silicon-germanium (SiGe) BiCMOS technology is proposed for Electrostatic Discharge (ESD) protection in this paper. The trigger voltage of the HTSCR is decided by the collector-to-emitter breakdown voltage of the HBT structure in floating base configuration (BVCEO). The underlying physical mechanisms critical to the trigger voltage are demonstrated based on the transmission line pulsing (TLP) measurement results and physics-based simulation results. The experiment results show that the trigger voltage of the fabricated HTSCR reduces to less 64% of that of the conventional MLSCR, and It2 of the HTSCR is 80% more than that of the conventional MLSCR. In order to reduce the chip area, an optimized HTSCR (OHTSCR) is also proposed. The OHTSCR has a smaller layout area and a lower trigger voltage.