Understanding the Basic Advantages of Bulk FinFETs for Sub- and Near-Threshold Logic Circuits From Device Measurements

This study aims to understand the potential of bulk FinFET technology from the perspective of sub- and near-threshold logic circuits down to 100-mV bias voltage. Measurements are performed on bulk FinFETs with a channel length of 60 nm, a fin height of 33 nm, and a fin width of only 14 nm and with a high- $k$/metal-gate stack having an equivalent thickness in inversion of 1.6 nm. For comparison purposes, measurements are also performed on bulk planar FETs with the same channel length and similar gate stack. FinFETs show a stronger dependence of the drain current on the gate voltage and a lower dependence on the drain and body biases w.r.t. planar devices. After adjusting for the different threshold voltages, FinFETs exhibit perfect balance between n- and p-FETs at any applied bias in the sub- and near-threshold regimes. As a consequence, FinFET logic circuits have significantly improved voltage scalability from the perspective of dc robustness and of performance/energy.