First Experimental Functionalization Results of SiC Nanopillars for Biosensing Applications

Abstract

DNA biosensors based on silicon carbide nanowire bioFET (SiC NW bioFET) benefit from both biocompatibility and semiconducting properties of SiC. One of the device realization key points is the functionalization of the SiC NW. This process is composed of two main steps: silanization and DNA grafting. It has been successfully carried out on both SiC single crystals and SiC nanopillars. Evidences of DNA detection are given by X-Ray photoelectron Spectroscopy (XPS) and fluorescence microscopy.

A silicon carbide nanowire field effect transistor for DNA detection

“…These layers do not involve charged species. Particularly regarding APTES, we previously showed using XPS analysis that the fraction of protonated amine was negligible [45]. So, as expected, these layers do not contribute to the provision of a significant field effect.…”

“…It is to be noted that un-passivated and OHdangling bonds on the SiC surface can act as surface trap states, the effects of which are detrimental for electrical characteristic measurements, as demonstrated in Si NWFETs [44]. The APTES film presence on the SiC surface was checked by XPS analysis [45]. Elsewhere, films made of other kinds of silane deposited on 6H-SiC planar surfaces have been thoroughly characterized by Schoell et al [48].…”

“…The complementary target strand sequence is 5′-CATAGAGTGGGTTTATCCA-3′. We have previously studied and validated DNA grafting and complementary hybridization on various SiC nanostructures using different characterization techniques such as XPS, fluorescence microscopy and AFM [42,45]. Furthermore, to test the In the present study, in view of confining the probes and target molecules on the SiC NW sensitive area, the functionalization process described above is locally performed on the chip by combining e-beam lithography and the chemical modification of the SiC NW surface (figure 4).…”

Silicon Carbide-Based DNA Sensing Technologies

“…Silicon (Si) is the backbone of the semiconductor industry [ 4 ] and one of the most commonly used materials for bio-sensing applications [ 5 ], mainly because of its electrical properties and well-established micro- and nanofabrication technologies [ 2 ]. However, Si can undergo chemical reactions in the body’s environment and is therefore not biocompatible [ 6 , 7 , 8 , 9 ] and suffers from instability in long-term uses in biological media and aqueous solutions, resulting in low signal-to-noise ratio and sensor performance issues [ 2 , 10 , 11 , 12 ]. Researchers have been exploring other materials for DNA sensing which are biocompatible, chemically inert and robust, and nontoxic to biomedical environments, such as gallium nitride (GaN) [ 5 ], carbon nanotubes (CNTs) [ 13 , 14 , 15 ], graphene [ 16 , 17 ], silicon carbide (SiC) [ 1 , 2 , 10 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 ], etc.…”

“…However, Si can undergo chemical reactions in the body’s environment and is therefore not biocompatible [ 6 , 7 , 8 , 9 ] and suffers from instability in long-term uses in biological media and aqueous solutions, resulting in low signal-to-noise ratio and sensor performance issues [ 2 , 10 , 11 , 12 ]. Researchers have been exploring other materials for DNA sensing which are biocompatible, chemically inert and robust, and nontoxic to biomedical environments, such as gallium nitride (GaN) [ 5 ], carbon nanotubes (CNTs) [ 13 , 14 , 15 ], graphene [ 16 , 17 ], silicon carbide (SiC) [ 1 , 2 , 10 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 ], etc. Among them, SiC is one of the most promising materials for DNA sensing.…”