The Si1-xNx:H film thickness dependence of surface passivation effect in the S1-xNx:H/SiO2 double-layer coating with hydrogen radical annealing, and reflectance spectra for various combination of SiO2 and Si1-xNx:H were investigated. The improvement of surface recombination velocity is caused by both the effective decrease of interface state density by hydrogen radical annealing and the field effect of positive charges induced in the Si1-xNx:H layer. Effective lifetime and C-V flatband shift were increased with increase of Si1-xNx:H layer thickness and saturates around 600 Angstrom. The combination of Si1-xNx:H(800 Angstrom) and SiO2(80 Angstrom) showed excellent passivation effects as well as good antireflection characteristics.