We investigated high quality semipolar (11-22) GaN epilayers were grown by novel 2-step growth method, which consisted of GaN (the first step) with N2 atmosphere and GaN (the second step) with H2 atmosphere at the growth temperature above 1000 οC without low temperature (LT) GaN or high temperature (HT) AlN buffer layer. As a nucleation layer, the thickness of GaN with N2 atmosphere was varied from 0.3 to 0.1 μm. The full width at half maximum (FWHM) of X-ray ω-rocking curve (XRC) was decreased from 1088 to 951 arcsec with reducing thickness of nucleation layer. After fixing 0.1 μm-thick GaN with N2 atmosphere, semipolar GaN epilayers were grown by controlling V/III, growth pressure and growth temperature under H2 atmosphere. From these results, we could achieve the minimum XRC FWHM of 602 arcsec with increasing V/III, growth pressure, and growth temperature.

Keywords: A1. High-resolution X-ray diffraction, A3. Metalorganic chemical vapor deposition, B1. Nitrides. PACS: 61.05.cp, 61.72.Uj, 68.55.ag, 78.67.De, 78.55.Cr.