The bipolar (underdamped sinusoidal) transient noise on power pins of CMOS integrated circuits (ICs) can trigger latchup in CMOS ICs under system-level electrostatic-discharge test. Two dominant parameters of bipolar transient noise-damping frequency and damping factor-strongly depend on system shielding, board-level noise filter, chip-/board-level layout, etc. The transient-induced-latchup (TLU) dependence on power-pin damping frequency and damping factor was characterized by device simulation and verified by experimental measurement. From the simulation results, bipolar-trigger waveforms with damping frequencies of several tens of megahertz can trigger the TLU most easily. However, TLU is less sensitive to the bipolar-trigger waveforms with an excessively large damping factor or an excessively low/high damping frequency. The simulation results have been experimentally verified with the silicon-controlled-rectifier (SCR) test structures that are fabricated in a 0.25-μm CMOS technology.
- Bipolar-trigger voltage
- Silicon-controlled rectifier (SCR)
- System-level electrostatic-discharge (ESD) test
- Transient-induced latchup (TLU)