Wafer‐Scale Selective‐Area Deposition of Nanoscale Metal Oxide Features Using Vapor Saturation into Patterned Poly(methyl methacrylate) Templates

Polymer Patterning: Patterning was accomplished using a Raith 150 TWO electron beam lithography system. Test samples were used to determine proper dosing times for varying thicknesses of PMMA. For example, 200 nm PMMA was patterned with an area dose of 180 uC cm -2 and a line dose of 900 pC. Patterns were developed in 1:3 isopropyl alcohol: methyl isobutyl ketone (Acros) for 55 s and then isopropyl alcohol alone for additional 30 s. PMMA acts as a positive photoresist where the areas exposed to the electron beam are removed. The Raith system is available through North Carolina State University's Nanofabrication Facility and was used to pattern PMMA features as small as 30 nm.