Silicon Nanowire Biosensor for Dengue Detection: Design, Fabrication and Characterization.

Silicon nanowires (SiNWs) have attracted significant interest in the study because of their potential to impact applications from nanoscale electronics to biomedical engineering. The SiNWs represent an important class of materials with their unique features such as identical diameters to biomolecules, enable to apply in biomolecule or chemical detection and can be fabricated as highly sensitive biosensor device. Thus, this study demonstrates the process development of SiNWs biosensor requires both the fabrication of nanoscale diameter wires and standard integration CMOS process. In order to use the fabricated device in DNA hybridization detection, the SiNWs surface was modified using APTES and glutaraldehyde to form a linker for further immobilization process. Contact angle measurement, fourier transform infrared spectroscopy and x-ray photoelectron spectrometer was carried out to study the effectiveness of these modification protocol. The hybridization of amine terminated probe DNA with complementary DNA was monitored by the resistance change that results from the accumulation of negative charge on the p-type APTES modified SiNW.

Figure 1:
(a) Cross section view of the SiNW with 50nm height and 60nm widthfabricated on the SiO2 layer,
(b) High power microscope (HPM) image of single and array SiNW
(C) HPM image of aligned SiNW with electrode pad
(d) I-V characteristic of SiNW as a sensor in response of different target DNA and
(e) thedetection principle of SiNW : binding of DNA (negative charge) on p-type NW resulting in accumulation of holes carrier, thus increase the conductance.

Prepared by: Siti Fatimah Abd Rahman (GS32185)