FinFET-Based Flex-Vth SRAM Design for Drastic Standby-Leakage-Current Reduction

Shin-ichi O'UCHI  Meishoku MASAHARA  Kazuhiko ENDO  Yongxun LIU  Takashi MATSUKAWA  Kunihiro SAKAMOTO  Toshihiro SEKIGAWA  Hanpei KOIKE  Eiichi SUZUKI  

IEICE TRANSACTIONS on Electronics   Vol.E91-C    No.4    pp.534-542
Publication Date: 2008/04/01
Online ISSN: 1745-1353
DOI: 10.1093/ietele/e91-c.4.534
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Section on Advanced Technologies in Digital LSIs and Memories)
SRAM,  FinFET,  4T-FinFET,  standby power,  dynamic threshold-voltage control,  

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Aiming at drastically reducing standby leakage current, an SRAM using Four-Terminal- (4T-) FinFETs, named Flex-Vth SRAM, with a dynamic row-by-row threshold voltage control (RRTC) was developed. The Flex-Vth SRAM realizes an extremely low standby-leakage current thanks to the flexible threshold-voltage (Vth) controllability of the 4T-FinFETs, while its access speed and static noise margin (SNM) are maintained. A TCAD-based Monte Carlo simulation indicates that even when the process-induced random variation in the device performance is taken into account, the Flex-Vth SRAM reduces the leakage current to 1/100 of that of a standard SRAM in a 256256 array, where 20-nm-gate-length technologies with the same on-current are assumed.