Fabrication of Broadband Antireflective Sub-Micro Structures on 4H-SiC by Mesh Patterning Etching

An approach to fabricating pseudoperiodic antireflective subwavelength structures on silicon carbide by using modified resist as etching mask is demonstrated. The etched submicron structure is a mesh-trenched pattern thus as the so called “mesh patterning etching”. The mesh patterning process is more time-efficient than the e-beam lithography or nanoimprint lithography process. The influences of the reactive-ion etching conditions and post bake temperature of the resist film to the sub-micron structure profile and its corresponding surface reflectance have been systematically investigated. Under optimal experimental conditions, the average reflectance of the silicon carbide in the range of 390-800 nm is dramatically suppressed from 40% to around 8% after introducing the mesh patterning sub-micro structures.