The potential of neutral beams for deep silicon nanostructure etching

Abstract

The potential of using hyperthermal neutral beams for etching high aspect ratio Si nanostructures is investigated through simulation. Advantageous aspects over the conventional plasma etching processes are predicted. Ultra high aspect ratio trenches with good anisotropy can be fabricated by neutral beam etching without (as necessary for conventional deep Si plasma etching) sidewall passivation. Sidewall bowing is a possible artefact. Inverse etching lag is predicted, and the neutral flux at the bottom of the structures, and consequently etching, can be sustained in structures with much higher aspect ratio compared with the case of conventional deep Si plasma etching.