| 摘要 |
PROBLEM TO BE SOLVED: To provide a group III nitride crystal, more excellent in crystal quality rather than conventional one, and also to provide its formation method. SOLUTION: Heat treatment at a predetermined temperature of 1,250°C or more is carried out to a base substrate wherein a first group III nitride crystal is formed as a growth base layer 2 by epitaxial formation in a predetermined substrate. Consequently, three-dimensional fine concavo-convex shapes made by an island shaped crystal 2I are formed on the surface of the growth base layer 2. On the above base substrate, the epitaxial formation of a second group III nitride is performed so as to form a crystal layer 4. Although many minute airspaces 5 are interposed at the interface of the crystal layer 4 and a base substrate 3, since the transmission of transposition from the base substrate 3 is controlled by the existence of the air spaces 5, the transposition density of the crystal layer 4 is reduced. Accordingly, the crystal layer 4 of good crystal quality is acquired. COPYRIGHT: (C)2007,JPO&INPIT
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