Fig. 1.

(Color online) Nanoporous exchange device. (a) An early iteration of the exchange device with microporous membrane with an inset of the channels. (b) (1) A 500 nm thick silicon dioxide layer is patterned onto a bare silicon substrate. (2) Nanopores are then patterned with e-beam lithography and etched into the oxide layer with RIE. (3) Microchannels are patterned onto the wafer using conventional photolithography. (4) Microchannels are etched through the oxide layer followed by deep RIE etching into the silicon substrate. (5) Photoresist is removed from the wafer and (6) the nanopores are subsequently etched into the substrate. (7) Pore sizes are reduced with PECVD and ALD oxide deposition.