Wafer-scale fabrication of CMOS-compatible, high aspect ratio encapsulated nanochannels

Nanochannels are key structures in nanofluidics for a variety of different applications. However, typical nanochannel fabrication methods are ill-suited for full integration with other microfabricatedcomponents or devices. Here, nanochannels with an aspect ratio (length to cross-sectional dimension) of greater than 400 000 were demonstrated—where the width (35–40 nm) and height (140–150 nm) of the channels are sufficiently small to elongate macromolecules—at channel lengths on the order of millimeters. These channels were fabricated with a CMOS-compatible toolset, allowing for the batch fabrication of a multitude of channels and with the further potential of full integration with solid-state electronic and photonic devices on the same wafer. Finally, the versatility of the nanochannel fabrication platform was demonstrated by loading the channels with six different liquids, and it was verified that the fluid flow dynamics for each liquid can be well estimated with Washburn's equation.