Performance Study of DM-DG-OS JL-MOSFET Based Biosensor in Detecting Charged Nanometric Biospecies

Abstract

In this paper, for the first time, a dual-metal double-gate with oxide stack (low-k/high-k) junctionless MOSFET (DM-DG-OS JL-MOSFET) based sensor device has been explored for finding its suitability in detecting charged nanometric biospecies under dry environment condition. The analysis of sensing performance of the device for such detection is made in terms of the absolute and the relative changes in threshold voltage (Vth). The influence of work-function difference of dual metal gate electrodes, along with the position of nanogap cavity, on the sensing metrics has been thoroughly investigated. The impact of the cavity dimensions on sensitivity parameters of the projected device is also studied. An optimum cavity dimension, for channel length (Lch) of 1 µm, is found to be 400 nm × 10 nm in yielding measurable sensitivity parameters for charged nanometric biospecies detection. A device with 1-µm Lch exhibits superior sensitivity performance in terms of percentage improvements in the absolute and the relative changes in Vth for a higher drain-side gate-metal work-function (ϕM2) relative to source-side gate-metal work-function (ϕM1) for source-side cavity (400 nm × 10 nm) compared to the case when ϕM1>ϕM2 and the cavity is located near drain-side. Respective performance enhancements are found to be 30.7% and 74% for detection of negatively charged nanometric biospecies. The sensor devices with Lch of 50 nm show the similar trend.