Simulation-Based Sensitivity Analysis of GaAs/GaSb Heterojunction Polarity-Controlled TFET for Biosensing Applications

Dielectrically modulated heterostructure tunnel field effect transistor (TFET)-based biosensors have emerged as promising solutions for low-power, ultra-sensitive detection of bioanalytes. This paper introduces a GaAs/GaSb heterojunction polarity-controlled TFET (GaAs/GaSb HJ-PC-TFET) biosensor for label-free detection of biomolecules, employing a heteromaterial and a polarity control approach to enhance sensitivity and reduce fabrication complexity. The polarity control technique is used to form the p+ source regions, avoiding challenges associated with ultra-sharp doping concentration gradients, high thermal requirements, and complex fabrication processes. The sensing capabilities of the GaAs/GaSb HJ-PC-TFET biosensor is evaluated based on variations in drain current <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$(\mathbf{I}_{\mathbf{DS}})$</tex> in response to different biomolecules. To assess its performance, biomolecules with dielectric constants <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$(k)$</tex> ranging from 1 to 24 were examined. With a k-value of 24 for a neutral biomolecule, the proposed GaAs/GaSb HJ-PC-TFET biosensor has an <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathbf{I}_{\mathbf{DS}}$</tex> sensitivity of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$1.52 \times 10^{13}$</tex>. Higher sensitivity indicates, the GaAs/GaSb HJ-PC-TFET biosensor is a highly promising device for advanced biosensing applications.