Asymmetric Underlapped FinFETs for Near- and Super-Threshold Logic at Sub-10nm Technology Nodes

作者：Goud A Arun^*; Venkatesan Rangharajan; Raghunathan Anand; Roy Kaushik

来源：ACM Journal on Emerging Technologies in Computing Systems, 2017, 13(2): 23.

DOI：10.1145/2967615

• Asymmetric underlap
• direct source to drain tunneling
• short channel effects
• leakage
• optimization
• quantum simulation
• near-threshold
• super-threshold
• LEON3 processor

Extending double-gate FinFET scaling to sub-10nm technology regime requires device-engineering techniques for countering the rise of direct source to drain tunneling (DSDT), edge direct tunneling (EDT) and short channel effects (SCE) that degrade FinFET I-V characteristics. Symmetric underlap is effective for eliminating EDT, diminishing DSDT, and lowering the fringe component of gate capacitance. However, excessive symmetric underlap also lowers the on-current, which is mainly due to thermionic emission. In this work, it is demonstrated that at sub-10nm node, asymmetric underlapped FinFETs with slightly longer underlap toward drain side than source side are superior to symmetric underlapped FinFETs due to further improvement in I-on/I-off and reduction in gate-to-drain capacitance. Using quantum mechanical device simulations, FinFETs with various degrees of underlap have been analyzed for improvement in I-V characteristics. A FinFET model for circuit simulations has been constructed that captures the major sub-10nm leakage components, namely, thermionic emission, DSDT, EDT, direct gate oxide tunneling and its associated components. By simulating a 10-stage NAND circuit and a LEON3 processor with interconnect parasitics using these devices, it is shown that asymmetric underlap instead of symmetric underlap in sub-10nm FinFETs can offer lower energy consumption with improved performance for near-threshold logic and higher energy-efficiency for super-threshold logic operation.

• 出版日期2017-3