A low-environmental-load single-crystal Si solar-cell fabrication method was demonstrated, in which SiN x :H anti-reflection film was formed using a pulsed-DC reactive sputtering method with Ar and a forming gas (FG: 3.8% H 2 in N 2 ), and an n + emitter was created using thermal diffusion of diluted phosphoric acid. In the SiN x :H film, it was shown that both exposure of the Si surface to FG plasma and FG annealing of the SiN x :H film dramatically decreased the surface recombination velocity, S, of the Si substrate, because of an improved Si/SiN x :H interface. The interface state density was found to be 2.1 ' 10 11 cm %2 &eV %1 and the minimum S was 72 cm&s %1 ; these values are comparable to those obtained using the plasma-enhanced chemical vapor deposition method. The characteristics of the fabricated solar cells were: a short-circuit current of 38.1 A&cm %2 , open-circuit voltage of 594.6 V, fill factor of 73.8, and an energy conversion efficiency of 16.7%.