Direct writing of ZrO₂ on a sub-10 nm scale using an electron beam

We describe a direct write technique using an electron beam to pattern ZrO₂ on a sub-10 nm scale that bypasses the conventional method of sputtering and lift-off. This technique utilizes spin-coatable ZrO₂ resist prepared by chemically reacting zirconium n-butoxide with benzoyl acetone in ethanol. The patterned resist has a sensitivity and contrast of ∼40 mC cm^-2 and 3, respectively. Baking the resist at 85°C increases the sensitivity to ∼9 mC cm^-2. The electron-beam-exposed regions become insoluble in acetone, thus yielding negative patterns. This property was exploited to write high-resolution patterns as small as 9 nm wide. Such negative patterns can be written with a pitch as close as 30 nm.