Nanoscale rings from silicon-containing triblock terpolymers

Nanoscopic ring arrays of various materials show promise for both technological applications and fundamental studies. In this work we report the preparation of sub-50 nm diameter ring arrays from metallic thin films using a block polymer lithographic pattern transfer approach. We prepared a triblock terpolymer that adopts a core-shell cylindrical morphology where the shell is an oxidizable polydimethylsiloxane block. Solvent annealed thin films of this terpolymer produce cylindrical features oriented perpendicular to the substrate surface. The polydimethylsiloxane shell is then converted into SiO _x rings by an oxygen reactive ion etch. The resultant hard mask pattern is then transferred into Au, Ni ₈₀Fe ₂₀, and Ni ₈₀Cr ₂₀ thin films via Ar ion beam milling, demonstrating the generality of the approach.