Negative electron-beam resist hard mask ion beam etching process for the fabrication of nanoscale magnetic tunnel junctions J. Vac. Sci. Technol. B 30, 06FA01 (2012); 10.1116/1.4767123 Long nanoscale gaps on III-V substrates by electron beam lithography J. Vac. Sci. Technol. B 30, 06F305 (2012); 10.1116/1.4766881 Nanomachining and clamping point optimization of silicon carbon nitride resonators using low voltage electron beam lithography and cold development J. Vac. Sci. Technol. B 28, C6P36 (2010); 10.1116/1.3517683Accurate control of remaining resist depth for nanoscale three-dimensional structures in electron-beam grayscale lithography J.The authors report a systematic investigation, both by experiment and by numerical modeling, of resolution limits for dense nanoscale gratings fabricated in polymethylmethacrylate through low-energy electron-beam lithography ͑EBL͒ using 10 keV electrons. In particular, they have studied the resist morphologies that develop in various exposure regimes for gratings with periods from 20 to 100 nm and categorized the potential sources of resist damage in such gratings. Through comparison of their experimental and numerical results, they have elucidated the major mechanisms that limit the EBL process resolution at the stages of exposure and resist development. The authors have also suggested semiempirical criteria to predict the risk of resist damage when fabricating dense nanostructures.