Investigation of N + SiGe juntionless vertical TFET with gate stack for gas sensing application

In this work, a novel N + SiGe delta-doped gate stacked junctionless vertical tunnel field transistor (N + SiGe gate staked JL-VTFET) is proposed and investigated with its electrical characteristics for gas sensing application using the Silvaco TCAD simulation software. This vertical distribution of the source, channel, and drain will enhance the stability of the device. The integrated effects of vertical tunneling as compared to lateral tunneling will enhance the device sensitivity and decrease the subthreshold slope. The gate stacking of High-K (HfO 2 ) with (SiO 2 ) and the two-side gate metal electrode makes a good electrostatic control over a proposed device. Also, the presence of SiGe layer in between the source-channel interface will lead to the decrease in the tunneling barrier and enhance the device performance by reducing the energy bandgap from 1.1 eV to 0.7 eV. This paper analyses hydrogen gas using palladium and ammonia gas using Cobalt and Molybdenum metals as a gate electrode. Utilizing work function values appropriate for the above metals, p + regions are generated close to the source field. By using the Silvaco ATLAS TCAD simulator, the proposed structure’s characteristics are investigated using the surface potential, electric field and energy bandgap diagrams for gas molecule adsorption on metal surface. The reported sensitivity (~ S Idoff ) is higher for the lower work function for Molybdenum, Cobalt and Palladium is 8.89 × 10 2 , 2.04 × 10 3 and 1.97 × 10 3 with high I don /I doff current ratio (~ 6.4 × 10 4 , 9.45 × 10 7 , 1.1 × 10 11 ), respectively.