Surface composition driven rippling of oblique Ar+ irradiated SiC/Si(111) thin films

Abstract

Oblique ion beam patterned and structured thin films hold promise as an advanced material for applications to photonics, micro- to nano-electronics, electro-optical and electrochemical devices fabrication. Herein, for the first time, we report the fabrication of patterned and structured SiC thin films over Si(111) by obliquely incident Ar⁺ beam. We show that at a short time scale, carbon clusters possessing nano-dimensional size evolve while ripple structures with direction parallel to the ion beam projection emerge at later time scales. The roughness evolution plot follows exponential and power law scaling at low and high bombarding time (in terms of ion fluence). The underlying mechanism is the altered surface layer composition due to the non-stoichiometric sputtering of silicon and carbon. The optical bands corresponding to silicon carbide (3.27–4.23 eV) & silicon (1.15–1.45 eV) co-exist for lower argon ion fluences while optical bands of silicon (1.15- 1.45 eV) remains and silicon carbide vanishes for higher argon ion fluences. Our experimental findings demonstrated the fabrication of ripple patterns over radiation tolerant, thermally and physically stable SiC by large area irradiation and capability to tailor the temporal characteristics of these evolved structures.