Impact of AC voltage stress on core NMOSFETs TDDB in FinFET and planar technologies

In this work, we explore the impact of AC stress voltage, frequency and duty cycle, on HK/metal gate core NMOSFET TDDB in FinFETs and planar technologies. Three observations are made: 1) Ratio of power on AC/DC decreases below 1kHz (~0.25 at 10Hz) and increases at higher frequencies (~5-10 at 100kHz). 2) Reducing the duty cycles also leads to a gain in AC/DC ratio. 3) Area scaled Weibull β shows a reduction (β_AC = ~0.9 × β_DC) at high frequencies while voltage acceleration (VAE) increases (VAE_AC = 1.18 × VAE_DC). Based on our study ~100mV gain in product V
_max
is projected under AC stress in MHz or higher range.