Self-Heating Aware Threshold Voltage Modulation Conforming to Process and Ambient Temperature Variation for Reliable Nanosheet FET

Abstract

Internal and external process variations severely affect the device threshold voltage $(\mathrm{V}_{\text{th}})$ and, in turn, the device's reliability. For the first time, this paper presented a thorough analysis of the self-heating aware $\mathrm{V}_{\text{th}}$ variation of a Nanosheet FET and, thus, the device's aging. Using well-calibrated TCAD models, we evaluated the 'change in $V_{th}\ ^{\prime}$ and performed an extensive design space exploration to analyze: (i) the impact of work function (WF) modulation owing to metal grain sizes and effective grains (for confined dimensions) on $\mathrm{V}_{\text{th}}$ variation; (ii) the impact of ambient temperature (TA) on $\mathrm{V}_{\text{th}}$ variation; (iii) the influence of trap charges on device characteristics; (iv) how the consideration of RDF impacted $\mathrm{V}_{\text{th}};$ (v) the device's aging, i.e., end of a lifetime (EOL). These investigations provided guidelines for designing a reliable Nanosheet FET (NSFET) to investigate and mitigate early aging.