Monolithic Wafer Scale Integration of Silicon Nanoribbon Sensors with CMOS for Lab-on-Chip Application.

Ganesh Jayakumar,Per-Erik Hellström,Mikael Östling

doi:10.3390/mi9110544

Ganesh Jayakumar, Per-Erik Hellström + Show 1 more

Open Access

https://doi.org/10.3390/mi9110544

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Journal: Micromachines	Publication Date: Oct 25, 2018
Citations: 3	License type: CC BY 4.0

Affiliation: KTH Royal Institute of Technology

Abstract

Silicon ribbons (SiRi) have been well-established as highly sensitive transducers for biosensing applications thanks to their high surface to volume ratio. However, selective and multiplexed detection of biomarkers remains a challenge. Further, very few attempts have been made to integrate SiRi with complementary-metal-oxide-semiconductor (CMOS) circuits to form a complete lab-on-chip (LOC). Integration of SiRi with CMOS will facilitate real time detection of the output signal and provide a compact small sized LOC. Here, we propose a novel pixel based SiRi device monolithically integrated with CMOS field-effect-transistors (FET) for real-time selective multiplexed detection. The SiRi pixels are fabricated on a silicon-on-insulator wafer using a top-down method. Each pixel houses a control FET, fluid-gate (FG) and SiRi sensor. The pixel is controlled by simultaneously applying frontgate (VG) and backgate voltage (VBG). The liquid potential can be monitored using the FG. We report the transfer characteristics (ID-VG) of N- and P-type SiRi pixels. Further, the ID-VG characteristics of the SiRis are studied at different VBG. The application of VBG to turn ON the SiRi modulates the subthreshold slope (SS) and threshold voltage (VTH) of the control FET. Particularly, N-type pixels cannot be turned OFF due to the control NFET operating in the strong inversion regime. This is due to large VBG (≥25 V) application to turn ON the SiRi sensor. Conversely, the P-type SiRi sensors do not require large VBG to switch ON. Thus, P-type pixels exhibit excellent ION/IOFF ≥ 106, SS of 70–80 mV/dec and VTH of 0.5 V. These promising results will empower the large-scale cost-efficient production of SiRi based LOC sensors.

Highlights

Silicon ribbon (SiRi) field-effect-transistors (FETs) have been widely recognized as efficient standalone prostate specific antigen (PSA) cancer marker, DNA, virus and pH sensors [1,2,3,4,5,6,7,8,9]
A single pixel sensor comprised of a control metal-oxide-semiconductor field-effect transistors (MOSFETs), an on-chip fluid-gate and a SiRi sensor connected at its output
From the ID-voltage to the backgate (VBG) characteristics in the backgate mode, it is found that the N- and P-type pixels exhibit similar characteristics to that of N- and P-type MOSFETs, respectively, with a subthreshold slope (SS) of 70–80 mV/dec and ION/IOFF ≥ 106

Summary

Introduction

Silicon ribbon (SiRi) field-effect-transistors (FETs) have been widely recognized as efficient standalone prostate specific antigen (PSA) cancer marker, DNA, virus and pH sensors [1,2,3,4,5,6,7,8,9]. The small size, high surface to volume ratio, electrical read-out and a dimension that is comparable to the target of interest make SiRi-FETs an excellent contender for label-free pH and bio detection [1,2,3,4,5,6,7,8,9]. The sensing mechanism of the SiRi-FET is based on the principle of detection of surface charge (Figure 1). The current flowing through the SiRi is measured without any DNA hybridization and its threshold voltage is noted (Vth1) (Figure 1a). The surface of the SiRi is functionalized with the receptors and target of interest such as a double stranded DNA. The addition of DNA molecule on the surface and the resulting.

CMOS CMOInStIengtreagtiroantion

SiRi Drain

SSiRiRi iDDimimeennsisoionnss

Electrical Parameter

Conclusions