An In-Depth Study on Device Variability in 22 nm FD-SOI NMOSFETs Under X-Ray Exposure

Le résumé fourni par la source

The effect of total-ionizing-dose (TID) on device-to-device variability in 22 nm FD-SOI NMOS transistors was experimentally quantified. Across tenW/Lgeometries, two device types (RVT, LVT), and three irradiation-bias conditions (Off-Stress, Work-Mode, Power-Off), ensembles ofN= 80 devices per geometry, 4800 transistors in total were irradiated to 300 krad(SiO2) and subsequently characterized. Pelgrom plots ofVthand the current-factor β were analyzed. TID consistently shiftedVthnegative and broadened its distribution while preserving the 1/ √WLlaw; the extractedAVthincreased by about 9–47% depending on bias/type, with a robust orderingOff-Stress>Work-Mode>Power-Off. In contrast, β exhibited near-zero mean drift and only modest variance growth (typically ≤20%), indicating a much weaker mobility-driven response. Size-segregated fits confirmed anarea-dominatedmechanism: small-area devices exhibited the largest variance increase, whereas large-area devices approached the measurement floor. A compact dose-aware Pelgrom model was established, adding a TID-dependent term toAVththat links the Poisson-distributed BOX trapped charge and the bias-dependent electrostatic coupling, and captures the observed bias ordering and size scaling.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.