Disclosed is a solar cell including: a semiconductor substrate; a conductive region on or at the semiconductor substrate; an electrode electrically connected to the conductive region; and a passivation layer on a light incident surface of the semiconductor substrate. The passivation layer includes a first layer in contact with the light incident surface of the semiconductor substrate and formed of silicon oxynitride for ultraviolet stability. The first layer includes a plurality of phases of the silicon oxynitride, and the plurality of phases are formed of the silicon oxynitride having different compositions.