Single-nanometer-scale electron and ion-beam lithography: Writing with Ångström-wide beams

Understanding the fundamental interactions of charged-particle beams with matter is key to pushing the boundaries of both electron- and ion-beam lithography. Improving our understanding of these interactions may enable us to pattern materials with higher areal densities than currently possible. 

State-of-the-art aberration-corrected electron microscopes developed in the last 20 years allow us to produce electron beams that are narrower than typical chemical bonds. These aberration-corrected microscopes allow us probe the resolution limits of electron-beam lithography and better understand how and where energy is deposited by electron beams in lithographic materials. 

Collective oscillations of electrons known as volume plasmons are a major energy-loss pathway for energetic electron beams as they propagate in materials. Volume plasmons can transfer energy over distances of about 10 nm in lithographic materials, thus impeding high-density patterning on the sub-10-nm length scale. Helium-ion-beam lithography will be introduced as a potential route to negate volume plasmon excitations and generate patterns with higher areal densities than previously demonstrated.