Simulation Study of Dual Metal-Gate Inverted T-Shaped TFET for Label-Free Biosensing

In this article, an inverted T-shaped tunnel field-effect transistor (TFET) with a dual metal gate (DMG) as a label-free biosensor has been proposed and analyzed using 3-D technology computer aided design (TCAD) simulations. The article compares the traditional inverted T-type TFET and the inverted T-type TFET with the DMG structure when used as a sensor. We focused on analyzing the electrical characteristics and sensitivity of the DMG structure and the single metal gate (SMG) structure as biosensors. The results show that the inverted T-shaped TFET biosensor with the DMG structure has better sensitivity and electrical characteristics. Compared with the SMG (work function = 4.3 eV), the DMG has a better ON-state current; compared with the SMG (work function = 3.8 eV), the DMG has a better subthreshold swing and sensitivity. In addition, the article also analyzed the influence of factors such as filling degree and temperature on the biosensor. The results show that the higher the filling level, the greater the ON-state current of the sensor. The higher the temperature, the greater the OFF-state current and the lower the sensitivity of the current switching ratio. Finally, a status map is presented, which maps the sensitivities of some important jobs in biosensor applications and the sensitivities of the proposed biosensors. The
$I_{\text{on}} / I_{\text{off}}$
sensitivity of the inverted T-shaped TFET biosensor is superior to those jobs.