Publication: The development of porcine biosensor using self limiting oxidation - atomic force microscope lithography
| datacite.subject.fos | oecd::Engineering and technology::Materials engineering | |
| dc.contributor.author | Nurain Najihah Binti Alias | |
| dc.date.accessioned | 2025-04-29T07:07:49Z | |
| dc.date.available | 2025-04-29T07:07:49Z | |
| dc.date.issued | 2023-08-01 | |
| dc.description.abstract | Silicon nanowires have been studied as biosensor due to excellent in detection of biological molecules. Silicon nanowire biosensor has a huge amount of potential to contribute to the field of biosensor for detecting deoxyribonucleic acid (DNA) molecules due to its distinctive electrical and nanostructure morphological qualities. In this research, silicon nanowires were fabricated using atomic force microscopy – local anodic oxidation (AFM-LAO) via top-down approach. AFM-LAO lithography is a non-destructive technique that provides precise and accurate patterning of nanoscale features without damaging the underlying material. According to prior research, the fabricated silicon sub-micron wires via AFM-LAO produced large range of width. The width of silicon nanowires was scaled down by using self-limiting oxidation (SLO) process to achieve the smallest possible width was studied. Firstly, silicon nanowire device was fabricated on p-type silicon-on-insulator (SOI) wafer via AFM-LAO and important parameters during AFM-LAO process was obtained. The obtained results indicate that the oxide patterns fabricated using Au-coated cantilever tip at 0.3 µm/s of writing speed and 9 V of applied voltage produce good structure of oxide patterns. Therefore, the AFM-LAO optimized parameter was used to fabricated oxide pattern for 5-wires, 10-wires, short-wires and long-wires devices. Then, the oxide patterns undergo silicon wet etching using the mixture of tetramethylammonium hydroxide (TMAH) with and without admixture of Triton X-100 and isopropyl alcohol (IPA) to etch the silicon layer. The surface roughness and wetting behaviour of APTES on etched SOI wafer was considered. The study found that the combination of the ternary solution, TMAH + Triton X-100 + IPA produced the lowest surface roughness which was 2.068 x 10-1 nm. It was also observed that, wetting behaviour of APTES on lowest surface roughness etched SOI wafer produced the most hydrophilic effect on the surface with 19.78 ° of contact angle. The hydrophilic behaviour of the SOI wafer indicates the presence of a high density of OH groups on its surface, facilitating the formation of hydrogen bonds with other molecules. This characteristic indirectly contributes to the more effective detection of porcine DNA in the biosensor. The silicon nanowires were then proceeded with the SLO process to reduce the width of fabricated silicon nanowire. The temperature, soaking time, gas flow rate and number of SLO cycles was investigated. The 1000 °C of temperature with three cycles of SLO removed the most oxide layer after oxide etching. Therefore, 1000 °C of temperature with three cycles of SLO was applied on fabrication of 5-wires, 10-wires, short-wires and long-wires devices. Lastly, silicon nanowire devices were functionalized with 3- aminopropyltriethoxysilane (APTES), glutaraldehyde and amine-terminated DNA to detect porcine DNA. The current-voltage (I-V) characteristics of devices were measured by using semiconductor parameter analysis (SPA) to investigate the device performance based on number of wires and length of wires. For different number of wires, device with 10-wires device obtained the highest sensitivity, 91.93 µAM-1 with 4.12 fM of LOD. While for different length of wires, short-wires device gained the highest sensitivity, 90.80 µAM-1 with 4.44 fM of LOD | |
| dc.identifier.uri | https://erepo.usm.my/handle/123456789/21467 | |
| dc.language.iso | en | |
| dc.title | The development of porcine biosensor using self limiting oxidation - atomic force microscope lithography | |
| dc.type | Resource Types::text::thesis::doctoral thesis | |
| dspace.entity.type | Publication | |
| oairecerif.author.affiliation | Universiti Sains Malaysia |