UTB GeOI 6T SRAM Cell and Sense Amplifier considering BTI Reliability

Abstract

This paper investigates the impacts of negative and positive bias temperature instabilities (NBTI and PBTI) on the stability of ultra-thin-body (UTB) GeOI 6T SRAM cell and performance of sense amplifier compared with the SOI counterparts. Worst case stress scenarios for read and write operations are analyzed. For UTB GeOI SRAMs, PBTI dominates the degradations in read static noise margin (RSNM), while for UTB SOI SRAMs, NBTI dominates the degradations in RSNM. Write static noise margin (WSNM) only slightly degrades due to NBTI and PBTI. Current latch sense amplifier (CLSA) and voltage latch sense amplifier (VLSA) are analyzed considering NBTI/PBTI for GeOI and SOI devices. GeOI CLSA and VLSA show smaller word-line to SAE buffer delay (T-BL) and sense amplifier sensing delay (T-SA) than the SOI counterparts. As aging time increases, GeOI CLSA and VLSA show larger degradations of T-SA than the SOI counterparts.