S. Sawara, M. Koh, T. Goto, Y. Ando, T. Shinada and Iwao Ohdomari
Appl. Surf. Sci.(to be published)
A simple process to fabricate two dimensional (2-D) concave nanopyramid array (NPA) with nano meter period on Si surface has been developed by using electron beam (EB) irradiation and wet etching. The enhanced etch rate of EB-exposed SiO2 in HF-based solution has been utilized. Mask oxide layers with the thicknesses of 11ム30 nm were shot with 30-keV focused EB at spot doses ranging from 20 to140 pC/dot. EB-exposed SiO2 layers were selectively etched by dipping in 1% HF or buffered HF (BHF). The Si substrates were then dipped in anisotropic etchant hydrazine (N2H4・H2O) to form concave NPAs, where patterned SiO2 layers were used as etch mask. By using this simple process, 50 nm period concave NPA with the size of 20 nm was fabricated successfully.