Design of NW TFET biosensor for enhanced sensitivity and sensing speed by using cavity extension and additional source electrode

Abstract

A planer structure of a tunnel field effect transistor (TFET) faces many consequences of fabrication complexity and less controllability of the gate electrode over the channel. Therefore, in this Letter nanowire TFET (NW TFET) is presented for the biosensing application. For this purpose, a new design approach of NW TFET has been presented to overcome the issues of planer structure TFET and for improving sensitivity and sensing speed of the biosensor. In this concern, an addition electrode is placed around the source region and the cavity, which is generally created in the oxide region under the gate electrode, is extended towards the source oxide region. Thus, due to the presence of source electrode, additional holes are accumulated in the source surface region and forming a plasma layer of holes. Hence, abruptness at source/channel junction is created. So as the biomolecules enter into the cavity, the large variation is observed in electrostatic properties of the device due to different properties (dielectric/charge) of the biomolecules. These variations reflect as improved sensitivity of the biomolecule detector. Further to this, because of the supplementary source electrode, abrupt source/channel junction provides lower subthreshold swing, which reduces the response time of the device and increases the sensing speed of biomolecules detection.