Fabrication of bottle-shaped nanochannels in fused silica using a self-closing effect

Abstract

The spatial control of molecular motor function, using nanostructured surfaces, is of great interest for the development of commercial devices for diagnostics and high-throughput drug screening with molecular motors as targets. In the present study we have fabricated 100-300nm wide nanochannels, completely subsurfaced on fused silica chips, with the aim to interface them with a microfluidic system. Such a system will allow for changes in the chemical environment surrounding molecular motors, with minimal influence on their directional motion. This will be achieved by changing the chemical environment in a perpendicular direction to the motor motion and allowing the chemical substances to diffuse in and out of the nanochannels via a small slit (5-10nm) on the top of the nanochannels. To create this slit, and to control its width, we here demonstrate the use of a self-closing effect based on the volume increase (2.27 times) during oxidation of silicon. The details of the fabrication steps (EBL, RIE and oxidation) are discussed.