| 摘要 |
PROBLEM TO BE SOLVED: To obtain an improvement of a crystal quality in a III nitride crystal, without providing a particular limit in a manufacturing condition. SOLUTION: An epitaxial substrate 10 is constituted of a base material 1 of a single crystal and an upper layer 2 consisting of a III nitride crystal film epitaxially formed on the main surface of the base material 1. This epitaxial substrate 10 is subjected to heat treatment at a temperature of 1,650°C under a nitrogen atmosphere. As a result, occurrence of pits on the surface is reduced, and it is confirmed that such a heat treatment is effective for an improvement of a surface flatness of the III nitride crystal. Moreover, it is also confirmed that a dislocation density in the III nitride crystal is 1/2 or less. COPYRIGHT: (C)2007,JPO&INPIT
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