Dielectric Modulated Biosensor Architecture: Tunneling or Accumulation Based Transistor?

Abstract

In this paper, we present a feasibility assessment of tunneling and accumulation mode p-type transistor architectures for use as dielectric-modulated biosensors. The performance of devices is compared through the estimation of the change in electrical characteristics between Iris antigen (bioreceptor) and anti-Iris antigen (target biomolecule) for a partially filled cavity. While tunnel field-effect transistors (TFETs) achieve higher sensitivity when biomolecules are positioned at the source-channel junction, the sensitivity rapidly diminishes when biomolecules are located away from the tunneling junction and, thus, severely limits their utility. Although accumulation mode field-effect transistors (AMFETs) also exhibit location-dependent sensitivity degradation, they show higher sensitivity values in comparison to the TFET for biomolecule layer located away from the source-channel junction. Furthermore, the application of back bias (~1 V) significantly improves the sensitivity (>8) for 40% filled cavity of p-type AMFET biosensors for all locations in the dielectric cavity. As higher sensitivity values over a wider biomolecule location are desirable, an AMFET performs better in comparison to the TFET cavity-modulated biosensor. This paper presents a systematic analysis, highlighting the benefits and limitations of each device for biosensing applications. Results highlight new viewpoints and insights in the design of AMFET-based cavity-modulated biosensors.