Negative Capacitance Gate-All-Around Tunnel FETs for Highly Sensitive Label-Free Biosensors

We propose a nanoscale, highly sensitive and label-free biosensor based on negative capacitance gate-all-around tunnel field-effect transistor (NC-GAA-TFET). NC-GAA-TFETs provide steeper, sub-60 mV/dec subthreshold swing (SS) and higher drive current compared with the conventional gate-all-around tunnel field-effect transistor (GAA-TFETs). The combination of differential voltage amplification, due to the negative capacitance (NC) of the gate ferroelectric, and the quantum mechanical band-to-band tunneling (BTBT) effect leads to a significant boost in current sensitivity (
${S}_{I}$
) compared with the state-of-the-art field-effect transistor (FET)-based sensing devices. 1-D Landau–Khalatnikov (L-K) equations are solved numerically and integrated with 3-D technology computer-aided design (TCAD) simulations to evaluate the sensor performance. The results show that the proposed sensor can achieve SS down to 27 mV/dec. The subthermal SS can be maintained over five decades of current leading to reduced power consumption in the weak inversion region and achieving
${S}_{I}$
as high as ~10
⁶
and ~10
⁵
for detecting biomolecules and pH changes, respectively. In addition, NC-GAA-TFETs provide ~
$7\times $
higher signal-to-noise ratio (SNR) than their baseline counterparts which make NC-GAA-TFETs promising candidates for low noise and ultrasensitive biosensing platforms.