This thesis focuses on high stabilized conversion efficiency of alternately hydrogen diluted multilayer solar cells. Through the optimization of p, p/i buffer layer, multilayer solar cell has low degradation rate and high stabilized conversion efficiency compared to amorphous silicon solar cell which is fabricated by pure $SiH_4$ gas. Multilayer solar cell has initial conversion efficiency of 8.86% and stabilized conversion efficiency of 8.00% after 20 hour light-soaking. Therefore, Multilayer solar cell has just degradation rate of 9.4%. On the other hand amorphous silicon solar cell has initial conversion efficiency of 10.3% and conversion efficiency of 7.68% after 20 hour light-soaking. Conversion efficiency of amorphous silicon solar cell after 20 hour light-soaking isn’t a stabilized conversion efficiency because that of amorphous silicon solar cell decreases after 20 hour light-soaking. But conversion efficiency of multilayer has no change after 20 hour light-soaking. And then alternately hydrogen diluted multilayer solar cell has low degradation effect during light-soaking