Nanolithography with metastabile helium

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 molecules are enough to write patterns into this resist. An edge resolution of 30 nanometers is demonstrated. The writing mechanism is based on the damage of the resist due to Penning ionization.