Effect of STI stress on leakage and Vccmin of a sub-65 nm node low-power SRAM

Abstract

In the paper, for the first time, the effects of shallow trench isolation (STI) stress enhanced boron diffusion on band-to-band (BTBT) leakage and Vccmin of a 65 nm node low-power SRAM are investigated in detail. High temperature oxidation in the STI process induces an elastic stress to enhance the diffusion of boron dopants, thus leading to a significant increase in BTBT on the STI edge sidewall. The enhanced boron diffusion is more serious for a shorter and/or narrower device, thus worsening the mismatch of the threshold voltage and Vccmin of the devices in a 65 nm node SRAM cell significantly.