Bipolar Transistors’ Holding Phenomena

Silicon Controlled Rectifier (SCR) is often applied for Electrostatic Discharge (ESD) protections. SCR holding voltage is requested to be larger than the integrated circuit (IC) operation voltage because SCR owns the latch-up phenomena. Bipolar transistors are more frequently than SCR to be used as ESD protections. Large holding voltages are also often requested for bipolar transistors. SCR owns the positive feedback circuit characteristics so it owns latch-up properties. However, bipolar transistors don’t have the positive feedback circuit so the latch-up event should not occur. The latch-up characteristics in SCR and not in bipolar transistors are discovered well in this study through the silicon verifications.