Current filament movement and silicon melting in an ESD-robust DENMOS transistor

HBM and TLP results for an 80 V DENMOS transistor are analyzed and simulated. The current is found to initially crowd into a small filament (to achieve its 2D 18.5 mA/mum snapback current density) which moves to cooler regions during the extent of the pulse. The mechanism and controlling factors for this filament movement, including lateral base-pumping, are investigated and quantified for general transistors. For the particular transistor, silicon melting (or some high-temperature electrical property change) is thereby deemed likely. A 3x improvement in the TLP damage current by adding parallel capacitance is also explained.