Nanopatterning of diamond films with composite oxide mask of metal octylates in electron beam lithography

The fabrication of diamond nanopatterns by electron cyclotron resonance (ECR) oxygen plasma with a composite metal octylate mask was investigated using electron beam lithography technology. A high etching selectivity of 14 was obtained with Bi₄Ti₃O₁₂ octylate film as a mask under the plasma-etching conditions of microwave power of 300 W and oxygen gas flow rate of 3 sccm. The metal naphthenates and metal octylates exhibited negative exposure characteristics. The sensitivity of metal naphthenates (1.2×10^–3 C cm^–2) was ten times lower than that of polymethyl methacrylate (PMMA) resist, while that of octylates (8.0×10^–5 C cm^–2) was in good agreement with that of PMMA resist (6.0×10^–5 C cm^–2). The resulting minimum chemical vapor deposited (CVD) diamond line-width of 100 nm with a height of approximately 1 m was fabricated with a Bi₄Ti₃O₁₂ octylate mask.