Nanochannel fabrication for chemical sensors

Abstract

In a novel chemical sensor, the chemical charge coupled device(CCD),electrostatic fields in nanocapillary channels smaller than a Debye length will be used to separate and concentrate ions in solution with a predicted detection limit of <1× 10 −13 M. Conventional integrated circuit techniques are used to deposit thin dielectric and amorphous-Si films on a Si substrate and to lithographically define channel and reservoir structures. Hollow Si 3 N 4 nanochannels with heights between 20 and 100 nm, widths between 0.5 and 20 μm, and lengths up to 5 mm have been fabricated by wet chemical etching of a sacrificial amorphous-Si layer in tetramethylammonium hydroxide. Initial modeling of a three-phase chemical CCD predicts the ability to select and concentrate ionic constituents by many orders of magnitude, according to their diffusion coefficients.