Fabrication of SiC Nano-pore arrays Structure by Metal-assisted Photochemical Etching

Silicon carbide (SiC) is widely used for electronic devices in high temperature and harsh conditions because of its excellent properties. However, SiC is difficult to processed effectively by the traditional wet etching method due to its excellent chemical stability. In this paper, a metal-assisted photochemical etching method was proposed and controllable nano-pore arrays structure in SiC was fabricated. By sputtering a noble metal layer on the bottom surface of the SiC wafer and illuminating UV light on the top surface, SiC could be effectively etched in etchant of hydrofluoric acid and hydrogen dioxide. The effective etching of SiC is attributed to the synergistic effect of abundant photogenerated holes excited by UV light and rapid electron transmission enhanced by the Pt layer, thereby, enhancing the etching reaction rate. Further, it was demonstrated that the diameter of nano-pores could be controlled by adjusting the time of plasma etching polystyrene spheres or changing the etching time. This work will provide an effective means to process wide band gap semiconductor.