A Dielectrically Modulated GaN/AlN/AlGaN MOSHEMT with a Nanogap Embedded Cavity for Biosensing Applications

Abstract

In this work, GaN/AlN/AlGaN MOS-HEMT with a cavity below the gate towards the drain side is studied for its sensitivity analysis and viability as a biosensor. The analysis is done by dielectric modulation of the cavity region to emulate the presence of different dielectric biomolecules and charged biomolecules by interface charge variation. MOSFET-based dielectrically modulated sensors have been a success experimentally and this work extends and demonstrates this concept with GaN HEMT. The device performance is evaluated through the shift in threshold voltage (V_th) and drain current (I_DS), which are used as performance metrics. The proposed device structure simulations were performed with ATLAS Silvaco device simulation tool which depicts the bio-immobilization in the cavity leads to the changes in electrostatic properties like conduction band offset, two-dimensional electron gas (2DEG) sheet carrier concentration and channel potential. The simulation analysis reveals V_th and I_DS shift up to 1.1 V and 153.7 mA/mm for the neutral biomolecules, whereas for deoxyribo nucleic acid, the shift is up to 0.30 mV and 65.2 mA/mm, respectively, implying a highly sensitive device. The AlGaN layer thickness and cavity fill height variations on device sensitivity are also reported.

KEYWORDS:

• Biosensor
• Dielectric-modulated
• DNA
• Embedded cavity
• GaN/AlGaN
• HEMT

ACKNOWLEDGEMENTS

The authors would like to extend their sincere gratitude to Department of Science and Technology-Science and Engineering Research Board for providing financial support through the sponsored project [Grant no: YSS/2015/000174] to carry out this research work.

Additional information

Funding

This work was supported by Science and Engineering Research Board: [Grant Number YSS/2015/000174].

Notes on contributors

Aasif Mohammad Bhat

Aasif Mohammad Bhat is working towards his PhD degree in the Department of Electronics and Communication, Malaviya National Institute of Technology, Jaipur, India. He received his BE degree in ECE from University of Kashmir in 2010 and MTech degree in ECE from Jamia Millia Islamia New Delhi, India, in 2018. His research interest includes modeling, simulation and fabrication of transistor-based sensors. E-mail: [email protected]

Arathy Varghese

Arathy Varghese is working towards her PhD degree in the Department of Electronics and Communication, Malaviya National Institute of Technology, Jaipur, India. She received her BTech degree in ECE from Government College of Engineering and Management Punnapra, Kerala, India, in 2013, and MTech degree in VLSI and embedded system from Saintgits College of Engineering Kottayam, Kerala, India, in 2015. Her research interest includes modeling, simulation and fabrication of transistor-based sensors. E-mail: [email protected]

Nawaz Shafi

Nawaz Shafi is working towards his PhD degree in the Department of Electronics and Communication, Malaviya National Institute of Technology, Jaipur, India. His research interest includes modeling, simulation and fabrication of transistor-based sensors. E-mail: [email protected]

C. Periasamy

C Periasamy received BE degree in ECE from Periyar University, Tamil Nadu, in 2002 and PhD degree in Electronics Engineering from IIT-BHU, Varanasi, India, in 2011. He is now working as an assistant professor in the Department of ECE, MNIT, Jaipur, India. He has published more than 65 papers in various international journals and conference proceedings. His research interest covers nanomaterial-based electronic and piezoelectric devices.