10-nm linewidth electron beam lithography on GaAs

Metal features with 10-nm linewidths were produced on thick GaAs substrates using electron beam lithography. A single layer of polymethylmethacrylate (PMMA) was exposed by an approximately 2-nm-diam electron beam with energies ranging from 20 to 120 keV. Gold-palladium lines less than 20 nm wide, and 15 nm thick, with center-to-center spacings of 70 nm, were produced over 15-μm square fields at all electron beam energies by lift off. The exposure latitude increased significantly for higher electron energies, with 10-nm-wide metal lines formed using a 120-keV writing beam.