Angled etching of Si by ClF3–Ar gas cluster injection

Abstract

Reactive gas cluster injection is an etching method that uses a neutral cluster beam without ions. This process can avoid damage caused by energetic ion irradiation and vacuum UV light from plasma. ClF3–Ar gas cluster injection was performed using a nozzle placed at various angles in the range of 0–78° from the normal to the sample. The Si substrate was anisotropically etched in the direction of the cluster beam, although the incident angle of the cluster beam was oblique. Oblique holes of 100 nm diameter and oblique square pillars of 3 µm width were fabricated with a high aspect ratio by angled cluster injection. It is expected that this process will create unprecedented structures for use in micro-electromechanical systems (MEMSs) or photonic crystals.