The external quantum efficiency of solar cells can be improved by using textured surface with minimum reflection. We have fabricated nanopillars and nanocone structures on silicon nitride surface by means of self-assembled nickel nano particle masks with single step inductively coupled plasma (ICP) ion etching and double step ICP etching, respectively. Thus, sub-wavelength nanopillar and nanoconelike structures displaying low reflectance were obtained readily without the need for any lithography equipment. The formation mechanism of nanopillar and nanocone like structures fabricated on silicon nitride surface has been discussed. The relationship of etching time with structure height and average reflectance spectra has been drawn.