Reduced subthreshold swing in a vertical tunnel FET using a low-work-function live metal strip and a low-k material at the drain.

Abstract

In this research paper, a vertical tunnel field-effect transistor (TFET) structure containing a live metal strip and a material with low dielectric constant is designed, and its performance metrics are analyzed in detail. Low-k SiO₂ is incorporated in the channel-drain region. A live molybdenum metal strip with low work function is placed in a high-k HfO₂ layer in the source-channel region. The device is examined by the parameters I _off, subthreshold swing, threshold voltage, and I _on/I _off ratio. The introduction of a live metal strip in the dielectric layer closer to the source-channel interface results in a minimum subthreshold slope and a good I _on/I _off ratio. The low-k material at the drain reduces the gate-to-drain capacitance. Both the SiO₂ layer and the live metal strip show excellent leakage current reduction to 1.4 × 10^-17 A/μm. The design provides a subthreshold swing of 5 mV/decade, which is an excellent improvement in TFETs, an on-current of 1.00 × 10^-5 A/μm, an I _on/I _off ratio of 7.14 × 10¹¹, and a threshold voltage of 0.28 V.