Design and fabrication of a nanofluidic channel by selective thermal oxidation and etching back of silicon dioxide made on a silicon substrate

Based on the law that the oxidation rate of Si decreases with the oxidation time, a method to fabricate a nanochannel is presented. In this method, the depth of the channel is precisely controlled by the oxidation time. Nanochannels are fabricated with depths of several tens of nanometers, width of 20 µm and lengths of several millimeters. SEM images show that the channel is fabricated well. It is shown that the flow rate increases linearly with the inlet pressure for water, NaCl solution and oil. Besides, the flow rate increases with the temperature. The capillary phenomenon is also observed in the nanochannel.