A solar cell is formed to have a silicon semiconductor substrate of a first conductive type; an emitter layer having a second conductive type opposite the first conductive type and formed on a first surface of the silicon semiconductor substrate; a back surface field layer having the first conductive type and formed on a second surface of the silicon semiconductor substrate opposite to the first surface; and wherein the emitter layer includes at least a first shallow doping area and the back surface field layer includes at least a second shallow doping area, and wherein a thickness of the first shallow doping area of the emitter layer is different from a thickness of the second shallow doping area of the back surface field layer.