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The behavior of gate grounded vertically stacked nanosheet N-FET (ggNFET) under ESD stress is investigated in this work. Single Fin (3-Sheet) ggNFET devices exhibit multiple instability points in the TLP-IV characteristic around the snapback region. Each of these instabilities was found to be arising due to non-uniform sheet turn-on and was independent of the presence of body contact. However, this instability was more severe, with a decreased body distance from the source. Furthermore, the sequence of turn-on was found to be dependent on the TLP current ramp rate. A 24-Fin (72 Sheet) ggNFET was simulated to reproduce the current filament like behavior. These 24- Fin simulations revealed a more severe low-current instability due to both non-uniform sheet turn-on and non-uniform Fin turn-on. For a smaller body to source contact distance, this non-uniform turn-on was seen to result in an early failure of the device.

Failure threshold in Fin based SCR (FinSCR) was found to be severely limited by the non-uniform current distribution across the anode/cathode fins, attributed to non-uniform turn-on of individual fins.Unique physical insights related to FinSCR turn-on uniformity and position of hot-spot are developed as a function of the placement of n- & p- tap Fins relative to cathode and anode fins. Based on the understanding, unique tap schemes are explored in FinSCR, which offered relaxed self-heating, improved turn-on uniformity and I T2 . A novel Distributed Tap FinSCR (DTFSCR) device is proposed, which offers uniform conduction i.e. failure threshold scalability with the number of fins in the anode & cathode regions. Finally, the effect of placement of ESD implants in the anode and cathode regions are discussed.