| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for obtaining a self-standing substrate by removing a single crystal base material from a laminated material where a single crystal layer formed of a nitride of AlN system group III is formed on the single crystal base material. SOLUTION: A substrate 1 includes, on a single crystal sapphire base material 1a, an underlayer 1b for growth formed of a nitride epitaxial film of the A1N system group III. The laminated material 3 forming a signal crystal layer 2 formed of the nitride of the AlN system group III on the substrate 1 is heated to the temperature of 1,400°C or higher, under the condition that only a base material 1a is exposed to the non-oxidation atmosphere having no oxidation capability for the single crystal sapphire to constitute the base material 1a. Accordingly, thermal decomposition of the base material 1a is generated, and a substance is produced which may be easily removed by wiping and adsorption, etc. Since dislocation on the side of the single crystal layer 2 is reduced with heat treatment, a self-standing substrate is obtained having excellent crystal quality formed of the single crystal nitride of the AlN system group III. COPYRIGHT: (C)2008,JPO&INPIT
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