Nanometer patterning of epitaxial CoSi₂ on silicon-on-insulator substrates

Nanometer patterning of thin single crystalline CoSi₂ layers on silicon-on-insulator (SOI) by local oxidation was studied. A nitride mask on top of the silicide layer was patterned by optical lithography to create the local stress. During the subsequent oxidation or oxynitridation, the silicide layer is separated at the edges of the nitride mask, where the stress is largest. The nanopatterning of the CoSi₂ layers was investigated under different oxidation ambients, and with different mask thicknesses. A feature size as small as 45 nm was obtained for 24 nm epitaxial CoSi₂ layers on SOI by this nanopatterning technique.