Statistical assessment of the full VG/VD degradation space using dedicated device arrays

Variability of as-fabricated (i.e., time-zero) parameters of modern VLSI devices has been considered in circuit design tools for some time. Also work on parametrizing time-dependent variability has been presented, with associated degradation mechanisms Random Telegraph Noise (RTN) and Bias Temperature Instabilities (BTI). Statistics on other FET degradation modes such as Hot Carrier Degradation (HCD) and Off-State-Stress (OSS) are, however, sparse. In this work, we design and measure a fabricated test array allowing us to capture degradation statistics, obtain the mean and the variance of multiple device degradation metrics (ΔV
_TH
, Δg
_m,...
) for an arbitrary (V
_G
, V
_D
) combination and show that time-dependent variability induced by channel HCD in deeply scaled devices is much more severe than (positive) BTI-induced variability.