Semiconductor light emitting element having a plurality of substrate cutouts and semiconductor layer side surface projections

In a semiconductor light emitting element (1) having a sapphire substrate (100), and lower (210) and upper (220) semiconductor layers laminated on the sapphire substrate, the substrate includes a substrate top surface (113), a substrate bottom surface (114), first substrate side surfaces (111) and second substrate side surfaces (112); plural first (121a) and second (122a) cutouts are provided at a border between the first substrate side surface, the second substrate side surface and the substrate top surface; the lower semiconductor layer includes a lower semiconductor bottom surface, a lower semiconductor top surface (213), first lower semiconductor side surfaces (211) and second lower semiconductor side surfaces (212); plural first projecting portions (211a) and plural first depressing portions (211b) are provided on the first lower semiconductor side surface; and plural second protruding portions (212a) and second flat portions (212b) are provided on the second lower semiconductor side surface.