TCAD Modeling of ESD Diode Overshoot During Ultrafast TLP Events

This study exploits Technology Computer-Aided Design (TCAD) simulations to investigate the voltage overshoot phenomenon in Electrostatic Discharge (ESD) protection diodes undergoing fast rise time pulses, which severely threatens integrated circuits reliability. The conventional TCAD approach for diode transient characterization, based on the thermodynamic transport model and neglecting avalanche generation in the forward bias region, is challenged based on a comparative simulation study. A more comprehensive approach relying on the hydrodynamic carrier transport model is proposed, solving mismatches between simulation results and experimental data of scaled devices operating in the picosecond regime. The improved prediction of diode overshoot allows for transient response optimization, which is essential for the tightly constrained protection design of high-speed interfaces. An approximate solution of the Boltzmann Transport Equation (BTE) using the Spherical Harmonic Expansion (SHE) method is also carried out to provide more physical insights, and the overshoot dependence on rise time is investigated.