Impact of Positive Charges in a Fringing Field Bio-Tunnel-FET Device with Source Underlap

In this paper, the sensitivity of the fringing field n-type tunneling field-effect transistor biosensor (Bio-nTFET) was investigated over the influence of positive fixed charges density (Q
_Bio
) and dielectric constant k, in the source underlap (L
_US
) region. Numerical simulations were performed using Sentaurus TCAD device simulator. The presence of different biomolecules, in the L
_US
region, affects the drain current of the on-state (I
_On
). It is shown that the sensitivity of the Bio-nTFET increases 3 orders of magnitude from k = 1 to k = 10 due to the improved fringing field that reduces the tunneling length resulting in a higher tunneling current. The sensibility also increases for a higher values of Q
_Bio
. The highest sensitivity value obtained in this work was 6.10
³
A/A for QBio = 1.10
¹²
cm
^-2
and k = 10. The proposed device shows great potential as a biosensor based on TFET devices.