Wet anisotropic etching for fluidic 1D nanochannels

In this paper a method is proposed to fabricate channels for fluidic applications with a depth in the nanometer range. Channels with smooth and straight sidewalls are constructed with the help of micromachining technology by etching shallow trenches into <110> silicon using native oxide as a mask material and OPD resist developer as the etchant. Sub-50 nm deep fluidic channels are formed after bonding the nanopatterned wafers with silicon or borofloat-glass wafers. The nanofabrication process is significantly simplified by using native oxide as the main mask material. The etch depth of the nanochannels is limited by the thickness of the native oxide layer, and by the selectivity of the oxide/silicon etch rate (estimated to be at least 250 for <110> silicon at room temperature).