Threshold Voltage Design and Performance Assessment of Hetero-Channel SRAM Cells

Optimized threshold voltage (Vt) design to enhance the variation immunity of high-performance (super-threshold) and low-voltage (near-/sub-threshold) 6 T SRAM cells is presented. For low-voltage SRAM cells operating at low Vdd, low-Vt design shows smaller variability, while the design tradeoff between performance and leakage should be considered. For high-performance SRAM cells operating at high Vdd, ultra-thin-body SOI SRAM cells with high-Vt design show smaller variability while sacrificing performance compared with the low-Vt design. Our study indicates that hetero-channel SRAM cells enable high-Vt design and exhibit improved Read/Write stability and performance, and maintain comparable RSNM variations for the high-performance SRAM applications.