US Patent 11088299 Group 13 element nitride layer, free-standing substrate and functional element

A crystal of a group 13 nitride has an upper surface and lower surface and is composed of a crystal of a group 13 nitride selected from gallium nitride, aluminum nitride, indium nitride or the mixed crystals thereof. When the upper surface of the layer of the crystal of the group 13 nitride is observed by cathode luminescence, the upper surface includes a linear high-luminance light-emitting part and a low-luminance light-emitting region adjacent to the high-luminance light-emitting part. A half value width of reflection at the (0002) plane of a X-ray rocking curve on the upper surface is 3000 seconds or less and 20 seconds or more.