Performance investigation of an InAs-based dielectric-modulated heterojunction TFET as a label-free biosensor

This work investigates the performance of an InAs-based dielectric-modulated heterojunction charge plasma-based tunnel field-effect transistor (DMH-CP-TFET) as a label-free biosensor. The nanogap cavity is created under the source electrode by etching out gate oxide material. The target biomolecules are modeled inside the nanogap cavity. The Dielectric Modulation technique and Charge-Plasma concept are utilized to investigate the biomolecules immobilized in the nanogap cavity. The presence of biomolecule inside the nanogap cavity changes the electrostatic potential, electric field, and capacitance of the device, and hence, the threshold voltage and drain current modulated. By measuring the change in the threshold voltage and drain current, the sensitivity of the device gets evaluated. The proposed device offers high electron mobility, narrow bandgap, and the ability to engineer heterojunctions to control charge carrier injection and tunneling properties. The simulated results show the I-ON sensitivity of 4.08 x 10(6) and I-ON/I-OFF sensitivity of 8.39 x 10(6) for neutral biomolecules (K = 12). The I-ON/I-OFF sensitivity is increased by 97.43% for positively charged biomolecules (1 x 10, K = 6) and 94.98% for negatively charged biomolecules (- 1 x 10, K = 6). The linearity analysis shows a strong correlation having Pearson coefficient, r > 0.97 is achieved for threshold voltage and subthreshold slope. The proposed device reports better sensitivity characteristics than the recent published heterojunction TFET biosensors. Silvaco TCAD ATLAS 2D device simulator is used to investigate the sensitivity, selectivity, and linearity of the proposed device for both neutral and charged biomolecules.