A Feasibility Study of Vertical Dual Channel Extended Source Schottky Barrier MOSFET as a Highly Sensitive Biosensor
الموضوعات : Journal of NanoanalysisMahshid Farahzadi 1 , Zahra Ahangari 2
1 - Department of Electronic, Yadegar- e- Imam Khomeini (RAH) Shahre Rey Branch, Islamic Azad University, Tehran, Iran
2 - Department of Electronic, Faculty of Electrical Engineering, Yadegar- e- Imam Khomeini (RAH) Shahr-e-Rey Branch, Islamic Azad University, Tehran, Iran
الکلمات المفتاحية: Dielectric Modulated Biosensor, Schottky Barrier MOSFET, Coefficient of Variation, Direct Tunneling, Thermionic Emission.,
ملخص المقالة :
In this research, we demonstrate an ultra-sensitive dielectric modulated biosensor based on vertical dual channel extended source Schottky barrier MOSFET. The proposed structure contains a nano-gap in which biomolecules are accumulated in it. The immobilization of biomolecules with different dielectric permittivity in the nano-gap modulates the effective gate capacitance and eventually results in the drain current deviation in comparison with the air- filled nano-gap condition. By definition, on-state and off-state current variation before and after biomolecule absorption are considered as two different measures for assessing the responsivity and sensitivity of the biosensor. Basically, the main focus of this paper is designing a low power device, in which the change in the electrical characteristics of the device under biomolecule absorption can be detected even in the absence of the gate bias. The high sensitivity of the proposed biosensor is mainly attributed to the extended source region which provides a wider current transport area at the interface of the source and channel regions. We optimize the bio sensing properties by exploring impact of critical physical and structural design parameters on the sensitivity and selectivity of the biosensor. In addition, statistical analysis is conducted to calculate coefficient of variation (CV) measure, for evaluating the change in the sensitivity of the biosensor based on variation of fundamental design measures. The results pave the way for designing a low power CMOS compatible biosensor that has fast response with high distinguishing selectivity and can be scaled down to nanoscale regime.
