Retention Problem Free High Density 4T SRAM cell with Adaptive Body Bias in 18nm FD-SOI

Publications

Retention Problem Free High Density 4T SRAM cell with Adaptive Body Bias in 18nm FD-SOI

Author : Dr Chandan Kumar

Year : 2022

Publisher : Institute of Electrical and Electronics Engineers Inc.

Source Title : Proceedings - 2022 35th International Conference on VLSI Design, VLSID 2022 - held concurrently with 2022 21st International Conference on Embedded Systems, ES 2022

Document Type :

Abstract

Area scaling of 6T SRAM cells has stagnated in advanced technology nodes [1]. The conventional 6T SRAM bitcell is bulky because of two pull-down NMOSs, which are sized to ensure cell stability. In this work, we present alternative 4T SRAM and 6T SRAM cells that eliminate these pull-down transistors. A 4T SRAM cell, so designed, is 10-13% denser than a 6T bitcell. 4T SRAM cells typically suffer from low data retention time and need to be refreshed regularly. We apply Adaptive Body Bias to alleviate the retention problem. In 18nm FD-SOI technology, the retention problem is completely mitigated, and leakage is reduced by 6× times that of 6T SRAM cells.