The goal of this work is to analyze the effect of the drain to gate and to biomaterial alignments on n-type Tunnel-FET (nTFET) working like a permittivity based biosensor. The biomaterial over the drain and channel region influence through the different dielectric permittivity material (k, where ɛ = k * ɛ 0 ) in the sensing area. The results show that the use of Tunnel-FET ambipolar current presents high sensitivity for using it as biosensor devices (Bio-TFET) for transistors with the drain to gate underlap (L UD ) of 27 nm and with minimum drain to biomaterial overlap (L over = 0) region.

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In this paper, we present a comprehensive study of the Fringing Field Biosensor Tunnel-FET (Bio-TFET) device based on 2D-device simulation. The presence of a biomaterial with a distinct dielectric constant (k, where ε = k*ε 0) on the underlap region (LUD) between gate and drain affects the ambipolar drain current (ID). The Bio-TFET can be observed in the ambipolar region (i.e., for negative gate voltage in an n type Bio-nTFET device) due to the variation of the k, biomaterial thicknesses (tBio), the LUD, and/or the presence of charges (QBio) into the biomaterial/silicon interface. The results show that the maximum sensitivity is observed when LUD = 30 nm (3 orders of magnitude higher compared with LUD of 25 nm lower or higher than 30 nm). When tBio increases from 10 nm to 30 nm (for k = 10), the sensitivity increases up to 1 orders of magnitude. The presence of QBio into the biomaterial also increases the sensitivity of 60 times for a fixed value of tBio = 30 nm and k = 10 and QBio changing from 1 × 1010 cm−2 to 1 × 1012 cm−2. The results show that the sensitivity of the fringing field Bio-nTFET is strongly dependent on the tunneling length modulation.

The goal of this work is to analyze the effect of gate to drain underlapping on n-type Tunnel-FET (nTFET) devices, filled with different dielectric permittivity material (k) in order to simulate the bio element materials. The results show that the use of Tunnel-FET ambipolar current presents high sensitivity for using it as biosensor devices for transistors with the drain underlap of 15 nm and total channel length of 50 nm for the range studied in this paper.