Modeling and Simulation of High-Sensitivity Silicon-Graphene TFET for Label-Free Biosensors

This paper proposes a Silicon-Graphene heterojunction barrier gate structure tunneling field effect transistor (SG-BG TFET) to solve the issue of low sensitivity in bio-detection. The sensor employs the dielectric modulation effect to achieve highly sensitive, label-free detection of biomolecules. The biomolecules are confined in the cavity under the barrier gate and distinguished by differing dielectric constants and charges. The sensor was modeled and simulated using the Silvaco TCAD software. The results show that the SG-BG TFET sensor effectively overcomes the bipolar problem in traditional graphene tunneling structures. The sensor displays a larger switching current ratio (1.24 × 10 13 ), a smaller subthreshold swing (4.8 mV dec −1 ), and a maximum current sensitivity of 8.85 × 10 12 and a tunneling voltage sensitivity of 1.02 V for the detection of neutral biomolecules with k = 12. Furthermore, this paper further analyzes the impact of doping concentration in the barrier region on the sensor’s sensitivity. Compared with other biosensors, the SG-BG TFET sensor has higher sensitivity and lower power consumption.