Patent attributes
An OECO solar cell using a semiconductor single crystal substrate having a plurality of grooves, wherein a minimum groove depth h of each groove always satisfies the relation of h≧W1tan θ where θ represents an angle between a line connecting the lower end, along the thickness-wise direction of the semiconductor single crystal substrate, of an electrode formed in the groove and the upper end of the inner side face of the same groove having no electrode formed thereon, and a reference line normal to the thickness-wise direction, and W1 represents a distance between both opening edges of the groove; wherein the semiconductor single crystal substrate has thickness decreasing from a first side of a first main surface to a second side opposed to the first side; and wherein the plurality of grooves have a depth distribution of being deepest at a thickest position of the substrate, and a gradually becoming shallower towards a thinnest position of the substrate.
