Submicron dry-etching behavior of β-FeSi2 thin films towards fabrication of photonic crystals

We have investigated dry-etching properties of polycrystalline β-FeSi2 films formed by ion-beam sputter-deposition (IBSD) and the films epitaxially grown on Si by metal organic chemical vapor deposition (MOCVD) in order to realize fabrication of photonic crystals with several hundreds nanometers in dimension. Using reactive ion etching with magnetic neutral loop discharge (NLD) plasma, we succeeded in realizing a comparatively higher etching rate than that obtained by inductively coupled plasma (ICP). Both reactive ion etching and impact ion etching modes may contribute to etching of β-FeSi2. We have fabricated a two-dimensional photonic crystal of β-FeSi2 on Si substrates and confirmed its predicted photonic properties in a reflectance spectrum of polarized light.