International Journal of Physical Sciences Vol. 7(22), pp. 2925 - 2934, 9 June, 2012 Available online at http://www.academicjournals.org/IJPS DOI: 10.5897/IJPS12.303 ISSN 1992 - 1950 ©2012 Academic Journals Full Length Research Paper Fabrication of 6 nm gap on silicon substrate for power- saving appliances T. S. Dhahi 1 *, U. Hashim 1 , M. E. Ali 2 and N. M. Ahmed 3 1 Institute of Nano Electronic Engineering, Universiti Malaysia Perlis, 01000 Kangar, Malaysia. 2 Nanotechnology and Catalysis Research Center, Universiti Malaya, 50603 Kuala Lumpur, Malaysia. 3 School of Physics, Universiti Sains Malaysia, 11800 Penang, Malaysia. Accepted 14 May, 2012 We document a thermal oxidation process for the reproducible fabrication of 6-nm gaps on silicon-on- insulator (SOI) substrate. Nanogaps sizes of this dimension are implicated to eliminate contributions from double-layer capacitance in the dielectric sensing of proteins or nucleic acids. The method combines conventional photolithography and pattern-size reduction technique to create a desired-size gap. The gaps are physically characterized with a field emission scanning electron microscopy (FESEM). Preliminary results show that gap-size reduction provides an improvement in conductivity, permittivity and capacitance parameters, reflecting the potential applications of the fabricated structures in low-power consuming electrical devices. The task is completed with two chrome masks: the first mask is for the nanogap pattern and the second one is for the electrodes. An improved resolution of pattern size is obtained by controlling the oxidation time of the final cycle. The reproducibility of the method is proven in triplicate experiments. We believe the method can be used in the industrial production of desired-size nanogaps on a variety of low-cost substrates. Key words: Nanogap, sequential oxidation, wet etching, double-layer capacitance, dielectric sensing, biomolecules. INTRODUCTION The main objective of the study is to fabricate an electrode with a desired nanogap on low-cost substrates. The development of a cost-effective, easily performable and high-throughput technique for the fabrication of such structures is of great interests both for the possibility of increasing the device-packing density and reducing the power consumption (Namatsu et al., 2003). Such structures might have potential applications in the next generation nano-electronic devices, such as single electron transistors (Namatsu et al., 2003), metal/ insulator tunnel transistors (Sasajima et al., 1999), nanowire transistors (Marchi et al., 2006), nanotube- or nanoparticle-based devices (Allen and Kichambare, 2007; Ding et al., 2006). Chemical and biological nanosensors, biochips and nanobioelectronics are other areas of potential applications and are rapidly *Corresponding author. E-mail: sthikra@yahoo.com. progressing (Schoning and Poghossian, 2006; Yogeswaren and Chen, 2008; Yih and Talpasanu, 2008, Poghossian et al., 2006). The coupling of biomolecules with nanomaterials (nanoparticles, nanotubes, etc) and nanostructures (e.g., nanoelectrodes, nanotransistors, nanogaps, nanopores, nanochannels) of comparable dimensions might allow the creation of hybrid systems with unique functions and applications (Tang et al., 2006; Zhang et al., 2008; Sigalov et al., 2008; Gun et al., 2008; Tsai et al., 2005; Liang and Chou, 2008; Cho et al., 2008). Such a functional hybrid systems, originated from the “marriage” of biomolecules and nano-scaled trans- ducers, provide a powerful tool, not only for manipulation and detection, but also for the fundamental research of single biological molecule (DNA, immunoglobulins, proteins, etc, and living cells). The realization of different nanometer-sized structures has been demonstrated by advanced high-resolution nanolithography techniques, such as electron- or ion- beam lithography, focused ion-beam milling, scanning