標題: FinFET SRAM Cell Optimization Considering Temporal Variability Due to NBTI/PBTI, Surface Orientation and Various Gate Dielectrics
作者: Hu, Vita Pi-Ho
Fan, Ming-Long
Hsieh, Chien-Yu
Su, Pin
Chuang, Ching-Te
電子工程學系及電子研究所
Department of Electronics Engineering and Institute of Electronics
關鍵字: FinFET;negative bias temperature instability (NBTI);positive bias temperature instability (PBTI);static random access memory (SRAM);surface orientation;variability
公開日期: 1-Mar-2011
摘要: This paper analyzes the impacts of intrinsic process variations and negative bias temperature instability (NBTI)/positive BTI (PBTI)-induced time-dependent variations on the stability/variability of 6T FinFET static random access memory (SRAM) cells with various surface orientations and gate dielectrics. Due to quantum confinement, (110)-oriented pull-down n-channel FETs with fin line-edge roughness (LER) show larger Vread, 0 and Vtrip variations, thus degrading READ static noise margin (RSNM) and its variability. Pull-up p-channel FETs with fin LER that are (100)-oriented show larger Vwrite, 0 and Vtrip variations, hence degrade the variability of WRITE SNM. The combined effects of intrinsic process variations and NBTI/PBTI-induced statistical variations have been examined to optimize the FinFET SRAM cells. Worst-case stress scenario for SNM stability/variability is analyzed. With the presence of both NBTI and PBTI in high-k metal-gate FinFET SRAM, the RSNM suffers significant degradation as Vread, 0 increases, whereas Vtrip simultaneously decreases. Variability comparisons for FinFET SRAM cells with different gate stacks (SiO(2) and SiO(2)/HfO(2)) are also examined. Our paper indicates that the consideration of NBTI/PBTI-induced temporal variation changes the optimal choice of FinFET SRAM cell surface orientations in terms of the mu/sigma ratio in RSNM.
URI: http://dx.doi.org/10.1109/TED.2010.2099661
http://hdl.handle.net/11536/9247
ISSN: 0018-9383
DOI: 10.1109/TED.2010.2099661
期刊: IEEE TRANSACTIONS ON ELECTRON DEVICES
Volume: 58
Issue: 3
起始頁: 805
結束頁: 811
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