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Low-Power FET-Based Biosensors
Published in Suman Lata Tripathi, Sobhit Saxena, Sushanta Kumar Mohapatra, Advanced VLSI Design and Testability Issues, 2020
Prasantha R. Mudimela, Rekha Chaudhary
A biosensor, defined by the International Union of Pure and Applied Chemistry (IUPAC), is a device that uses specific biochemical reactions mediated by isolated enzymes, immune systems, tissues, organelles, or whole cells to detect chemical compounds by using electrical, thermal, or optical signals [1]. FET (field-effect transistor)-based biosensor (Bio-FET) is an electrically and chemically insulating layer that separates the analyte solution from the semiconducting device. The first Bio-FET developed by Piet Bergveld was the ion-sensitive field-effect transistor (ISFET) used for electrochemical and biological applications in 1970. The Bio-FET is a field-effect transistor (metal oxide semiconductor field-effect transistor [MOSFET] based) that is gated by variations in the surface potential induced by molecules binding. When charged molecules, such as biomolecules, bind to the FET gate, which is usually a dielectric material, they can change the charge distribution of the underlying semiconductor material resulting in a change in conductance of the FET channel. As shown in Figure 9.1, Bio-FET consists of two main compartments: (i) the biological recognition element and (ii) the FET. Its construction is basically centered on the ISFET, a type of MOSFET where the metal gate is substituted by a membrane, solution of electrolyte, and reference electrode.
Nanowire Transistors: A Next Step for the Low-Power Digital Technology
Published in IETE Journal of Research, 2021
D. Ajitha, K. N. V. S. Vijaya Lakshmi, K. Bhagya Lakshmi
The Nanowire technology can be used as the most basic component of the IC i.e. in place of the (FET). There are so many changes developed in the potentiometric sensors [45] based on FET. These also exhibit regular features of the normal classic MOSFET. All the FET-based devices are three-terminal configuration with a source, drain and gate. The metallic gate in MOSFETs is in direct contact with the dielectric over the channel, whereas the gate (reference) electrode in biological FET (BioFET) sensors is separated from the dielectric by a sample fluid. The surface potential, which acts as an extra gate voltage, is altered by changes at the dielectric-solution interface.