Patterned nanoscale materials with controllable characteristic feature sizes and periodicity are of considerable interest in a wide range of fields, with various possible applications ranging from biomedical to nanoelectronic devices. Block-copolymer (BC)-based lithography is a powerful tool for the fabrication of uniform, densely spaced nanometer-scale features over large areas. Following this bottom-up approach, nanoporous polymeric films can be deposited on any type of substrate. The nanoporous periodic template can be transferred to the underlying substrate by dry anisotropic etching. Nevertheless the physical sizes of the polymeric mask represent an important limitation in the implementation of suitable lithographic protocols based on BC technology, since the diameter and the center-to-center distance of the pores cannot be varied independently in this class of materials. This problem could be overcome by combining block copolymer technology with atomic layer deposition (ALD): by means of BC-based lithography a nanoporous SiO(2) template, with well-reproducible characteristic dimensions, can be fabricated and subsequently used as a backbone for the growth of perfectly conformal thin oxide films by ALD. In this work polystyrene-b-poly(methylmethacrylate) (PS-b-PMMA) BC and reactive ion etching are used to fabricate hexagonally packed 23 nm wide nanopores in a 50 nm thick SiO(2) matrix. By ALD deposition of Al(2)O(3) thin films onto the nanoporous SiO(2) templates, nanostructured Al(2)O(3) surfaces are obtained. By properly adjusting the thickness of the Al(2)O(3) film the dimension of the pores in the oxide films is progressively reduced, with nanometer precision, from the original size down to complete filling of the pores, thus providing a simple and fast strategy for the fabrication of nanoporous Al(2)O(3) surfaces with well-controllable feature size.
Andreozzi, A., Lamagna, L., Seguini, G., Fanciulli, M., Schamm Chardon, S., Castro, C., et al. (2011). The fabrication of tunable nanoporous oxide surfaces by block copolymer lithography and atomic layer deposition. NANOTECHNOLOGY, 22(33) [10.1088/0957-4484/22/33/335303].
The fabrication of tunable nanoporous oxide surfaces by block copolymer lithography and atomic layer deposition
FANCIULLI, MARCO;
2011
Abstract
Patterned nanoscale materials with controllable characteristic feature sizes and periodicity are of considerable interest in a wide range of fields, with various possible applications ranging from biomedical to nanoelectronic devices. Block-copolymer (BC)-based lithography is a powerful tool for the fabrication of uniform, densely spaced nanometer-scale features over large areas. Following this bottom-up approach, nanoporous polymeric films can be deposited on any type of substrate. The nanoporous periodic template can be transferred to the underlying substrate by dry anisotropic etching. Nevertheless the physical sizes of the polymeric mask represent an important limitation in the implementation of suitable lithographic protocols based on BC technology, since the diameter and the center-to-center distance of the pores cannot be varied independently in this class of materials. This problem could be overcome by combining block copolymer technology with atomic layer deposition (ALD): by means of BC-based lithography a nanoporous SiO(2) template, with well-reproducible characteristic dimensions, can be fabricated and subsequently used as a backbone for the growth of perfectly conformal thin oxide films by ALD. In this work polystyrene-b-poly(methylmethacrylate) (PS-b-PMMA) BC and reactive ion etching are used to fabricate hexagonally packed 23 nm wide nanopores in a 50 nm thick SiO(2) matrix. By ALD deposition of Al(2)O(3) thin films onto the nanoporous SiO(2) templates, nanostructured Al(2)O(3) surfaces are obtained. By properly adjusting the thickness of the Al(2)O(3) film the dimension of the pores in the oxide films is progressively reduced, with nanometer precision, from the original size down to complete filling of the pores, thus providing a simple and fast strategy for the fabrication of nanoporous Al(2)O(3) surfaces with well-controllable feature size.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.