Fabrication of High Aspect Ratio Silicon Nanochannel Arrays

Abstract

We report a method of fabricating an array of high aspect ratio silicon nanochannels which is not dependent on nanolithography techniques and equipment. The method comprises etching of silicon micro-channels in an inductively coupled plasma system (ICP), followed by a thermal oxidation step where silicon is consumed during the process to further shrink the channel to nano dimensions. For the micro-channel formation, silicon dioxide is used as the etch mask during the ICP process where a high etch selectivity of 70:1 between silicon and silicon dioxide was achieved. By thermally oxidizing the etched silicon channels, a uniform array of nanochannels with lateral dimensions down to 40 nm was achieved with significantly high aspect ratio value of at least 65. The grown thermal oxide uniformly covers all surfaces of the silicon nanochannels.