Design and Analysis of Junctionless Based Symmetric Nanogap-Embedded TFET Biosensor

Abstract

In the present paper, symmetrical configuration of dual material double gate dielectric modulated junctionless TFET (DM DG JLTFET) for biosensor applications is explored. The JLTFET consists of Si material with an intensely doped n-type substrate. In this work, the JLTFET utilizes the dielectric modulation method which aids the bio-transistor to recognize neutral and charged analytes (biomolecules). A double metal gate structure is designed by employing two dissimilar metal gate electrodes to reduce short channel impact on device characteristics. The proposed device includes a nanogap region (cavity) which is framed for biomolecules to immobilize. Surface potential and their sensitivity are examined for neutral and charged-neutral analytes. The effects of structure parameters such as nanogap region length and fill-in factor have been analyzed through simulation. The paper examines the behavior of DM DG JLTFET for biological molecules sensing via change in relative permittivity and charge density. The proposed device shows noticeable sensitivity results for charged biomolecules (especially for positively charged analytes). The present work has analyzed the different parameters affecting the sensitivity of the biosensor which includes structural geometric variations like change in cavity length, cavity thickness and fill-in factor. The sensitivity of the neutral biomolecules having higher dielectric constant is observed higher; the surface potential sensitivity of the Gelatin (k = 12) is estimated as $3.75\times {10}^3$ which is 45%, 55%, and 135% higher than the sensitivity of Keratin (k = 7), Bacteriophage T7 (k = 6), and Glucose Oxidase (k = 3), respectively at the cavity length of 7 nm.

KEYWORDS:

• Biosensor
• Double gate (DG)
• Drain current
• Label free detection
• Relative permittivity
• Tunnel FET

Additional information

Notes on contributors

Girish Wadhwa

Girish Wadhwa received the BTech degree in electronics and communication engineering from Kurukshetra University, Kurukshetra, Haryana India, in 2006 and the MTech degree from Mullana University, India, in 2011. He is currently working towards the PhD degree in electronics and communication Engineering at National Institute of Technology Jalandhar, Jalandhar, Punjab, India. He worked as assistant professor in the department of ECE at NIT Jalandhar, Punjab from 2013 to 2017. His research interest includes modeling and simulation of semiconductor devices, especially junctionless TFETs for biosensor applications.

Balwinder Raj

Balwinder Raj (MIEEE’2006) did BTech (Electronics Engineering) PTU Jalandhar, MTech (Microelectronics) PU Chandigarh and PhD (VLSI Design) IIT Roorkee, India in 2004, 2006 and 2010, respectively. He has completed postdoc at University of Rome, Tor Vergata, Italy in 2010–2011. Currently, he is working as Assistant Professor at NIT Jalandhar, Punjab, India since May 2012. Dr Raj worked as assistant professor at ABV-IIITM Gwalior from July 2011 to Apr 2012. He had received Best Teacher Award from Indian Society for Technical Education, New Delhi on 26th July 2013. Dr Raj also received Young Scientist Award from Punjab Academy of Sciences during 18th Punjab Science Congress. Dr Raj has authored/co-authored two books, three book chapters and more than 60 research papers in peer reviewed international/national journals and conferences. His areas of interest in research are classical/non-classical nanoscale semiconductor device modeling; FinFET based memory design, low power VLSI design, memristive devices, digital/analog VLSI design and FPGA implementation. E-mail: [email protected]