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 ( $1\bar {1}0$ ) 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/In1– n Al n As1– n Sb n 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 $10^{-3}$ A/m OFF-current ( $I_{\mathrm{\scriptscriptstyle OFF}}$ ) and a 0.3 V power supply, we simulate 270 A/m ON-current ( $I_{\mathrm{\scriptscriptstyle ON}}$ ) for a 30-nm gate length and 170 A/m for a 15-nm gate length $(L_{g})$ , while a conventional 15-nm $L_{g_{_{_{}}}}$ GaSb/InAs TFET under (001) confinement shows only 24 A/m $I_{\mathrm{\scriptscriptstyle ON}}$ .