Sensitivity and sensing speed analysis of extended nano-cavity and source over electrode in Si/SiGe based TFET biosensor

Abstract

In this manuscript, a new approach has been presented to enhance biosensor sensitivity and sensing speed by altering the mobility of charge carriers in the source region. The presented biosensor has been named as hetero material, source electrode tunnel FET, HM-SE-TFET. For comparison, we have considered P $$^{+}$$ (Source) N(Channel) N $$^{+}$$ (Drain) type architecture. In the proposed device, doped SiGe is used to enhance the mobility of charge carriers in the source region. Additionally, an extra negative biased source electrode is deposited over the source region, which overcomes the material solubility limit. The extra negative biased source electrode attracts the holes from bulk P $$^{+}$$ source which increases the abruptness at the source-channel interface. The increased abruptness at the junction increases the ON State driving current. Further, the cavity which was earlier under the gate electrode has been extended to the source region, which provides a large area to accommodate in the cavity and changes the electrostatic characteristics of the device. Hence the combined effect of hetero material (SiGe) in the source region and extension of cavity to the source region enhances the sensitivity and sensing speed of the biosensor. The effectiveness of the proposed biosensor has been compared with the conventional Si-based TFET biosensor in terms of drain current and device sensitivity.