We report results on optimization of ‘‘stable’’ amorphous silicon solar cells. Approaches used for optimization were based on hydrogen content variation in the intrinsic layer of p‐i‐n solar cells. Hydrogen content was varied in two ways: by changing the substrate temperature and by using hydrogen diluted silane during intrinsic layer deposition. Single junction solar cells of efficiencies greater than 7% after 600 hours of continuous light soaking were obtained. Single junction solar cells having microcrystalline intrinsic layers were prepared for the first time and show promise for use in the top cell of tandem modules.