High-Current Tunneling FETs With (110) Orientation and a Channel Heterojunction

Abstract

We propose InAs/GaSb ultrathin-body tunneling field-effect transistors (TFETs) using confinement in the (11̅0) plane and transport in the [110] direction to increase the tunneling probability by reducing the tunnel barrier energy and hole effective mass. To reduce the OFF-state leakage current, we add an InAs/In <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1-n</sub> Al <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">n</sub> As <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1-n</sub> Sb <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">n</sub> heterojunction to the channel, which increases the valence band barrier. The heterojunction also increases the tunneling probability and ON-current by reducing the tunneling distance through the p-n junction and introducing a resonant state. A fully atomistic non-equilibrium Green function quantum transport approach in NEMO5 is used to explore the design space. While choosing 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-3</sup> A/m OFF-current (I <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">OFF</sub> ) and a 0.3 V power supply, we simulate 270 A/m ON-current (I <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ON</sub> ) for a 30-nm gate length and 170 A/m for a 15-nm gate length (Lg), while a conventional 15-nm Lg GaSb/InAs TFET under (001) confinement shows only 24 A/m ION.