Paper MN+GR-ThM6
Nanostructuring of Ultrananocrystalline Diamond (UNCD) Thin Films Via Block Copolymer Lithography

Thursday, November 12, 2009, 9:40 am, Room A8

Diamond is in many ways an optimal material for numerous technological, industrial and biological applications because of its exceptional physical and chemical properties. In addition to high hardness, diamond is stiff, biocompatible and wear resistant. Nanopatterning of diamond surfaces is critical for the development of diamond-based MEMS/NEMS, such as resonators or switches. Micro/nano structuring of diamond materials is typically associated with conventional lithographies such as photolithography or electron beam lithography. In this paper, we demonstrate a simple process, known as block copolymer (BCP) lithography, of nanostructuring ultrananocrystalline diamond (UNCD) surfaces. In BCP lithography, nanoscale self-assembled polymeric domains serve as an etch mask for pattern transfer. We used thin films of a cylinder-forming organic–inorganic BCP, poly (styrene-block-ferrocenyldimethylsilane), PS-b-PFS, as an etch mask on UNCD. Orientational control of the etch masking cylindrical PFS blocks are achieved by manipulating the polymer film thickness in concert with the annealing treatment. For films much thinner than the equilibrium periodicity of the microdomains, the cylinders spontaneously orient themselves perpendicular to the substrate. On the other hand, films with thickness close to the equilibrium periodicity exhibit in-plane orientation. We have observed that surface roughness of UNCD plays an important role in transferring the pattern. Reactive ion etching (RIE) using oxygen gas was used to etch the exposed areas of UNCD. Arrays of both UNCD posts and wires have been created using the same starting polymeric materials as the etch mask.