Patent ID: 8415673

Claim:
A semiconductor layer, comprising a top surface, a bottom surface and a side surface, wherein: a tangential line to a portion of the side surface which is in the vicinity of a border with the top surface is inclined with respect to the normal to the bottom surface; and an angle made by a tangential line to a certain portion of the side surface which is farther from the top surface than the portion of the side surface in the vicinity of the border with the top surface, and a plane defined by the bottom surface, is larger than an angle made by the tangential line to the portion of the side surface in the vicinity of the border with the top surface and the plane defined by the bottom surface, the side surface including an inclining flat face, wherein the side surface further includes another inclining flat face having a different inclination angle with respect to the bottom surface from that of the inclining flat face; and an angle made by the inclining flat face and the plane defined by the bottom surface is smaller than an angle made by the another inclining flat face and the plane defined by the bottom surface.