Authors: J. Koohsorkhi, Y. Adbi, S. Mohajerzadeh, J. Derakhshandeh, H. Hosseinzadegan, A. Khakifirooz and M.D. Robertson
Affilation: University of Tehran, Iran, Islamic Republic of
Pages: 238 - 241
Keywords: carbon nanostructure, submicron lithography, self-defined, encapsulated lens, electron beam
We report a novel technique for submicron and nanolithography using vertically grown nickel seeded carbon nano-structures (CNS) on silicon substrates. The field emission characteristic of carbon nano-tubes is utilized to create nano-scale features. The structure used here consists of vertical CNT’s encapsulated with titanium-dioxide and chromium (or silver) bi-layers. While CNT is responsible for electron emission, the surrounding metal (separated from inner CNT by a dielectric layer) acts as a self-defined gate to control the level of electron emission as well as an integrated electrostatic lens for beam shaping. The process is completed after chemical mechanical polishing followed by plasma ashing to open up the nano-tips and to form partially hollow nano-pipes. By applying proper voltage between carbon tip(cathode) and a resist-coated substrate (anode) electrons are emitted from negative side and nano-size features are developed on the resist-coated positive side. Using this technique we have drawn lines with a width of 120nm and a length of 5-10µm. Also round dots with sizes smaller than 0.4µm were realized. Straight lines with a thickness less than 100nm have also been achieved, although thinner features are expected by more proper control on the gate electrode and distance between CNT emitter and resist-coated substrates.