| 摘要 |
PROBLEM TO BE SOLVED: To reduce an influence of an electric field due to polarization in operating a semiconductor element. SOLUTION: Crystals of GaN A-axis-oriented on a sapphire R plane (10-12) substrate are grown by the MOCVD method. First, the temperature of the sapphire substrate is raised to 1,000°C or higher, and the surface is cleaned by thermal treatment in an NH<SB>3</SB>atmosphere, an N<SB>2</SB>atmosphere or an H<SB>2</SB>atmosphere for example. Then, the temperature is lowered to 600°C or lower, and crystals of a low temperature GaN buffer layer are grown. Then, the temperature is raised to 1,000°C or higher, for growing the GaN layer by 1μm for example. Such a growing sequence forms a non-polarized A plane ((11-20) plane) nitride semiconductor free from a polarization electric field occurring in the depthwise direction. COPYRIGHT: (C)2007,JPO&INPIT
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