Group-III nitride laminated substrate and semiconductor element

A semiconductor element comprising, as at least a portion of an operating layer, a second layer included in a group III-nitride laminated substrate, the group III-nitride laminated substrate including:

• an underlying substrate;
• a first layer that is formed on the underlying substrate, wherein the first layer consists of aluminum nitride, with a top surface having Al-polarity;
• and
• a second layer that is formed on the top surface of the first layer and is made of gallium nitride,
• wherein the second layer has a thickness of 10 μm or less, a half-value width of (0002) diffraction determined through X-ray rocking curve analysis is 100 seconds or less, and a half-value width of (10-12) diffraction determined through X-ray rocking curve analysis is 200 seconds or less.

A group III-nitride laminated substrate comprising:

• an underlying substrate;
• and
• a first layer that is formed on the underlying substrate, wherein the first layer consists of aluminum nitride, with a top surface having Al-polarity,
• wherein the top surface of the first layer is to be used as a base for growth of a second layer that is made of gallium nitride and has a thickness of 10 μm or less and in which a half-value width of (0002) diffraction determined through X-ray rocking curve analysis is 100 seconds or less, and a half-value width of (10-12) diffraction determined through X-ray rocking curve analysis is 200 seconds or less.