Quasi-Schottky-Barrier UTBB SOI MOSFET for Low-Power Robust SRAMs

Abstract

This paper presents a low-power robust static random access memory (SRAM) using a novel quasi-Schottky-barrier ultrathin body and ultrathin buried oxide (UTBB) silicon-on-insulator (SOI) device. In the proposed device, the drain terminal is highly doped and a metallic source terminal is used. Given the proposed structure, asymmetric characteristics will be achieved according to the drain–source bias voltage ( ${V}_{\text {DS}})$ . These characteristics of the proposed device are extensively analyzed and compared with a conventional symmetric UTBB SOI device. The asymmetry nature of the proposed device will lead to the mitigated read–write conflict of the 6T-SRAM cell. The simulation results show a leakage reduction of 18% at ${V}_{\text {DD}} = 1$ V in comparison with the 6T-SRAM cell realized by conventional symmetric UTBB SOI device. Furthermore, in comparison with the conventional 6T-SRAM, the realized cell shows a 54% improvement in read static noise margin, 6.6% higher write margin, and $3.1\times $ faster write at the cost of a longer access time. To achieve a practical read access time, we utilize split bitline approach.