Design of Temperature-Aware Low-Voltage 8T SRAM in SOI Technology for High-Temperature Operation (25 %C–300 %C)

Abstract

A temperature-aware low-voltage 8T static random access memory (SRAM) for high-temperature operations is presented. A dedicated read port with virtual ground and optimal body bias improves sensing margin under very high temperature (up to 300 °C). Bitline offset voltage for data “0” caused by the virtual ground scheme is also compensated by a replica bitline. The independent body bias control feature of the employed silicon-on-insulator (SOI) technology allows the write margin to be enhanced significantly without using any write-assist circuitry. Test chips were fabricated in a 1- $\mu \text{m}$ SOI technology with tungsten interconnect for reliability at high temperature and lesser process variation. Measurement results demonstrate that the proposed SRAM operates successfully up to 300 °C with the supply voltage range of 2–5 V. At the minimum performance variation point ( $V_{\mathrm{ DD}} = 2.5$ V), the SRAM consumes 1.48 mW and shows the access time of 156 ns and the maximum clock frequency of 14.38 MHz at 300 °C.