Writing nanostructures with a metastable helium beam

We have used a self-assembling monolayer of dodecanethiole molecules as the resist for a lithography technique based on a beam of metastable helium atoms. Doses as low as 3 metastable helium atoms per 10 resist molecules are enough to write patterns. The writing mechanism is based on the Penning-ionization-induced changes of the local wetting properties of the surface. An edge resolution of 30 nanometers is demonstrated.