Applicability of Transconductance-to-Current Ratio ( $g_{\mathrm {m}}/I_{\mathrm {ds}}$ ) as a Sensing Metric for Tunnel FET Biosensors

Abstract

In this paper, we propose and evaluate the feasibility of transconductance-to-current ratio ( $g_{\mathrm {{m}}}/I_{\mathrm {{ds}}}$ ) as a sensing metric for a tunnel field-effect transistor (TFET)-based dielectric modulated biosensor. Focusing on the enhancement of the values of $g_{\mathrm {{m}}}/I_{\mathrm {{ds}}}$ and current ratio at lower current levels to signify the presence of biomolecules in the dielectric cavity of TFET biosensor, the metric can be used not only for sensitivity but also for selectivity as the current ratio changes appreciably for the three different types of biomolecules, namely, Streptavidin, Biotin, and APTES. The $g_{\mathrm {{m}}}/I_{\mathrm {{ds}}}$ extraction takes into account the operation at low power consumption, i.e., in the subthreshold region, which is most sensitive for biomolecule detection. The sensing methodology is governed by the location of the biomolecules within the cavity, and is less dependent on the fill-in factor. This paper highlights new opportunities to identify the sensing metric in TFET-based dielectric modulated biosensors.