A P+ pocket doped 4H–SiC Schottky barrier FET as highly sensitive label-free biosensor

In this paper, a 4H–SiC Schottky barrier field-effect transistor with a P⁺ doping Pocket based on dielectric modulation effect for label-free detection of biomolecules has been proposed. Upon optimization of the length and position of P⁺ doping pocket, the sensitivity of the biosensor achieves the maximum when it is located within the channel 1 nm away from the Schottky contact with a length of 5 nm. Simulations have been performed for different dielectric constants and biomolecules with different charge densities by Sentaurus TCAD. The results show that the new structure has an on-current sensitivity of 1.03 × 10⁸, a maximum transconductance sensitivity of 6.24 × 10⁷, a threshold voltage sensitivity of 65 mV, and an I_on/I_off ratio sensitivity of 1.8 × 10⁴ for neutral biomolecules with K = 12. In addition, the fill factor of the cavity and linearity of the proposed structure are considered in this paper. Further, the on-current sensitivity of our proposed structure is gauged against state of the art, which demonstrate a high sensitivity of our proposed biosensors. The smaller size and prominent sensitivity characteristics of the biosensor proposed in this paper have made it widely used in the field of biomedical detection that requires high integration and efficient detection.