Demonstration of improved heteroepitaxy, scaled gate stack and reduced interface states enabling heterojunction tunnel FETs with high drive current and high on-off ratio

Staggered tunnel junction (GaAs<sub>0.35</sub>Sb<sub>0.65</sub>/In<sub>0.7</sub>Ga<sub>0.3</sub>As) is used to demonstrate heterojunction tunnel FET (TFET) with the highest drive current, I<sub>on</sub>, of 135μA/μm and highest I<sub>on</sub>/I<sub>off</sub> ratio of 2.7×10<sup>4</sup> (V<sub>ds</sub>=0.5V, V<sub>on</sub>-V<sub>off</sub>=1.5V). Effective oxide thickness (EOT) scaling (using Al<sub>2</sub>O<sub>3</sub>/HfO<sub>2</sub> bilayer gate stack) coupled with pulsed I-V measurements (suppressing D<sub>it</sub> response) enable demonstration of steeper switching TFET.