University of Tehran Department of Electrical and Computer Engineering ISSCC 2013 / SESSION 18 / ADVANCED EMBEDDED SRAM / 18.1 A 20nm 112Mb SRAM in High-κ Metal-Gate with Assist Circuitry for Low-Leakage and Low-VMIN Applications by: Milad Zamani May 2013

Contents Introduction Proposed structure Implementation & Layout Conclusions Introduction Proposed structure Implementation & Layout Conclusions 1/17

SRAM Structure Stability Leakage Introduction Introduction SRAM Structure Stability Leakage 2/17

SRAM Structure ◦ Cell ◦ Decoder ◦ Sense Amplifier ◦ Write Driver ◦ Timing Introduction 3/17 SRAM Structure Stability Leakage Jan M. Rabaey, Anantha P. handrakasan, Borivoje Nikolić, “Digital integrated circuits: a design perspective”, Prentice Hall; 2 edition, January 3, 2003.

Stability ◦ Static Noise Margin (SNM) Introduction 4/17 SRAM Structure Stability Leakage Jan M. Rabaey, Anantha P. handrakasan, Borivoje Nikolić, “Digital integrated circuits: a design perspective”, Prentice Hall; 2 edition, January 3, 2003.

Stability ◦ Dynamic Noise Margin Introduction Seng Oon Toh; Zheng Guo; Liu, T.-J.K.; Nikolic, B.;, "Characterization of Dynamic SRAM Stability in 45 nm CMOS," Solid-State Circuits, IEEE Journal of, vol.46, no.11, pp , Nov /17 SRAM Structure Stability Leakage

Introduction 6/17 SRAM Structure Stability Leakage Subthreshold SRAM ◦ Leakage Current Verma, N.; Chandrakasan, A.P.;, "A 256 kb 65 nm 8T Subthreshold SRAM Employing Sense-Amplifier Redundancy," Solid-State Circuits, IEEE Journal of, vol.43, no.1, pp , Jan. 2008

Proposed Circuit PSWL & BT-NBL Proposed structure Proposed Circuit partially suppressed wordline (PSWL) scheme and bitline-length-tracked negative-bitline-boosting (BT- NBL) scheme Power management 7/17 Power management

Proposed structure 8/17 Proposed Circuit Chang, Jonathan; Chen, Yen-Huei; Cheng, Hank; Chan, Wei-Min; Liao, Hung-Jen; Li, Quincy; Chang, Stanley; Natarajan, Sreedhar; Lee, Robin; Wang, Ping-Wei; Lin, Shyue-Shyh; Wu, Chung-Cheng; Cheng, Kuan-Lun; Cao, Min; Chang, George H., "A 20nm 112Mb SRAM in High-к metal-gate with assist circuitry for low-leakage and low-VMIN applications," Solid-State Circuits Conference Digest of Technical Papers (ISSCC), 2013 PSWL & BT-NBL Power management

Proposed structure 9/17 Proposed Circuit Chang, Jonathan; Chen, Yen-Huei; Cheng, Hank; Chan, Wei-Min; Liao, Hung-Jen; Li, Quincy; Chang, Stanley; Natarajan, Sreedhar; Lee, Robin; Wang, Ping-Wei; Lin, Shyue-Shyh; Wu, Chung-Cheng; Cheng, Kuan-Lun; Cao, Min; Chang, George H., "A 20nm 112Mb SRAM in High-к metal-gate with assist circuitry for low-leakage and low-VMIN applications," Solid-State Circuits Conference Digest of Technical Papers (ISSCC), 2013 PSWL & BT-NBL Power management

Proposed structure 10/17 Proposed Circuit Chang, Jonathan; Chen, Yen-Huei; Cheng, Hank; Chan, Wei- Min; Liao, Hung-Jen; Li, Quincy; Chang, Stanley; Natarajan, Sreedhar; Lee, Robin; Wang, Ping-Wei; Lin, Shyue-Shyh; Wu, Chung-Cheng; Cheng, Kuan-Lun; Cao, Min; Chang, George H., "A 20nm 112Mb SRAM in High-к metal-gate with assist circuitry for low-leakage and low- VMIN applications," Solid-State Circuits Conference Digest of Technical Papers (ISSCC), 2013 PSWL & BT-NBL Power management

11/17 Implementation & Layout layout Structure layout

12/17 Implementation & Layout layout Structure

13/17 Implementation & Layout layout Structure Chang, Jonathan; Chen, Yen-Huei; Cheng, Hank; Chan, Wei-Min; Liao, Hung-Jen; Li, Quincy; Chang, Stanley; Natarajan, Sreedhar; Lee, Robin; Wang, Ping-Wei; Lin, Shyue-Shyh; Wu, Chung-Cheng; Cheng, Kuan-Lun; Cao, Min; Chang, George H., "A 20nm 112Mb SRAM in High-к metal-gate with assist circuitry for low-leakage and low-VMIN applications," Solid-State Circuits Conference Digest of Technical Papers (ISSCC), 2013

14/17 Implementation & Layout layout Structure The die area of the test-chip is 40.3mm2 with 448 (2048×134) SRAM macros Chang, Jonathan; Chen, Yen-Huei; Cheng, Hank; Chan, Wei-Min; Liao, Hung-Jen; Li, Quincy; Chang, Stanley; Natarajan, Sreedhar; Lee, Robin; Wang, Ping-Wei; Lin, Shyue-Shyh; Wu, Chung-Cheng; Cheng, Kuan-Lun; Cao, Min; Chang, George H., "A 20nm 112Mb SRAM in High-к metal-gate with assist circuitry for low-leakage and low-VMIN applications," Solid-State Circuits Conference Digest of Technical Papers (ISSCC), 2013

With the SD, PSD and DR power-management modes, the SRAM leakage current is reduced to 16.6% for full macro shut down, 44.7% of peripheral circuits shut down and 34.2% for the peripheral circuits shut down with arrays entering into data-retention mode Nothing about stability !!! Conclusion 15/16

Trends Trends 16/17

Trends Trends 17/17

Refrence Jan M. Rabaey, Anantha P. handrakasan, Borivoje Nikolić, “Digital integrated circuits: a design perspective”, Prentice Hall; 2 edition, January 3, Seng Oon Toh; Zheng Guo; Liu, T.-J.K.; Nikolic, B.;, "Characterization of Dynamic SRAM Stability in 45 nm CMOS," Solid-State Circuits, IEEE Journal of, vol.46, no.11, pp , Nov Verma, N.; Chandrakasan, A.P.;, "A 256 kb 65 nm 8T Subthreshold SRAM Employing Sense-Amplifier Redundancy," Solid-State Circuits, IEEE Journal of, vol.43, no.1, pp , Jan Chang, Jonathan; Chen, Yen-Huei; Cheng, Hank; Chan, Wei-Min; Liao, Hung-Jen; Li, Quincy; Chang, Stanley; Natarajan, Sreedhar; Lee, Robin; Wang, Ping-Wei; Lin, Shyue-Shyh; Wu, Chung-Cheng; Cheng, Kuan-Lun; Cao, Min; Chang, George H., "A 20nm 112Mb SRAM in High-к metal-gate with assist circuitry for low-leakage and low-VMIN applications," Solid-State Circuits Conference Digest of Technical Papers (ISSCC), 2013 Trends in ISSCC 2013