Analytical Vth Modeling for Dual-Gate MOSFETs With Independent Gate Control

We report a study on the threshold voltage (
${V}_{\text{th}}$
) description for dual-gate MOSFETs with independent gate control, which provides the major contribution for multigate MOSFETs. Specifically, we focus on the understanding of the control mechanisms with two gates, leading to the derivation of an appropriate
${V}_{\text{th}}$
description. The results demonstrate that
${g}_{m}$
-linear extrapolation (GMLE) method can extract a
${V}_{\text{th}}$
value, which reflects the device physics in the best way. Both front- and back-gate charges are found to induce important contributions to the threshold condition. The newly developed
${V}_{\text{th}}$
equation includes only device parameters and accurately predicts
${V}_{\text{th}}$
value for any back-gate bias conditions. Based on this
${V}_{\text{th}}$
model, a further analytical equation is derived for the situation, where the back-gate charge becomes comparable and starts to exceed the front-gate charge. The independent gate control induces two
${V}_{\text{th}}$
values if the back-gate control becomes strong enough in comparison to that of the front gate. It is further shown that the developed model can be applied for device performance optimization to meet circuitry requirements.