Direct Tailoring the Si Substrate for Antireflection via Random Nanohole Nanoimprint

In this paper, a 2 inch random nanohole Si template with hole diameter of 36-97 nm is employed for direct tailoring the Si substrate for antireflection. The random nanohole Si template is fabricated from the natural self-organization process and can be used repeatedly in nanoimprint lithography (NIL). The surface roughness induced from the nanohole structured surface enhanced the antiadhesion property (contact angle of 128°) of the Si template for high accuracy soft mold replication. The random nanohole structured polymer/Si substrate has a surface fluctuation of ~3 nm, which ensures a uniform and effective pattern transfer from resist to substrate. The reflectivity of the random nanohole structured Si substrate decreases from around 34% to less than 5% with the hole aspect ratio within 3.0 in the wavelength region of 400-800 nm. This method is simple, cheap, repeatable in large area and compatible with the high volume production lines.