| 摘要 |
This free-standing substrate is provided with: a first nitride layer which is grown by a hydride vapor deposition method or an ammonothermal method and is composed of a nitride of one or more elements selected from the group consisting of gallium, aluminum and indium; and a second nitride layer which is grown on the first nitride layer by a sodium flux method and is composed of a nitride of one or more elements selected from the group consisting of gallium, aluminum and indium. In the first nitride layer, a plurality of single crystal grains are arranged so as to extend between a pair of main surfaces of the first nitride layer. In the second nitride layer, a plurality of single crystal grains are arranged so as to extend between a pair of main surfaces of the second nitride layer. The thickness of the first nitride layer is larger than the thickness of the second nitride layer. |
