Nanolithography using spin-coatable ZrO₂resist and its application to sub-10 nm direct pattern transfer on compound semiconductors

A typical method for sub-micrometer compound semiconductor dry etching utilizes polymethylmethacrylate (PMMA) to transfer patterns to SiO(2) as intermediate masks, which limits its ability to obtain etching resolutions approaching sub-10 nm. We report a new approach for direct sub-10 nm pattern transfer using sol-gel derived spin-coatable ZrO(2) resist as the mask. The optimal dose of ZrO(2) resist is ∼160 mC cm(-2). The sample InP compound semiconductor etching selectivity to ZrO(2) is over 13:1, with high aspect ratio of 35:1. The smallest etching feature is 9 nm. These results will be very useful for realizing various challenging nanoscale photonic and electronic devices and circuits.