E-beam lithography of catalyst patterns for carbon nanotube growth on insulating substrates

We present a process for fabricating small catalyst particles for carbon nanotube growth on insulating substrates. For this purpose we define hydrogen silsesquioxane (HSQ) resist structures on top of conducting and grounded metallic catalyst layers and a sacrificial chromium layer, using e-beam lithography.The developed resist structures act as an etch mask in the subsequent ion milling step, by which the surrounding metal layers are removed. Having wet etched the Cr mask and HSQ resist, metal structures remain which serve as catalyst in a chemical vapour deposition (CVD) process resulting in single wall carbon nanotubes with a diameter range of 0.8–2.0 nm on insulating substrates.