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We perform an improved method of thermodynamic analysis for semipolar 11 2 ¯ 2 and 1 1 ¯ 01 surfaces of GaN and AlN to elucidate the relationship between growth conditions and semipolar and polar surfaces during metalorganic vapor phase epitaxy (MOVPE). The calculations for H2 carrier gas suggest that for both GaN and AlN the maximum temperature for growth on 11 2 ¯ 2 surfaces is higher than that for growth on 0001 surfaces. On the other hand, the maximum temperature for growth on GaN 1 1 ¯ 01 surfaces is comparable to that for growth on GaN 0001 surfaces, while the maximum temperature for the growth on AlN 0001 surfaces is higher than that for growth on AlN 1 1 ¯ 01 surfaces. These results could be used to provide favorable conditions for growth of group-III nitrides along a semipolar orientation during MOVPE.

An equilibrium Wulff construction using absolute surface energies for various orientations is conducted to elucidate the morphology change of GaN under the metalorganic vapor‐phase epitaxy (MOVPE) condition. The calculated equilibrium shapes suggest that the morphology mainly consists of {11¯01} and {11¯00} facets under Ga‐rich condition for selective area growth (SAG) on [ 11¯00 ] lateral direction. In contrast, an equilibrium crystal shape including the larger area of {11¯01} facets and (0001) plateau with smaller {11¯00} facets emerges under N‐rich condition. Furthermore, by incorporating growth conditions such as growth temperature and carrier gas, it is found that the (0001) plateau hardly emerges under H2 carrier gas condition at low temperature. The results under H2 carrier gas are found to be different from those under N2 carrier gas where the (0001) plateau slightly emerges at low temperature. The calculated results manifest that our approach can provide the determination of equilibrium shape of semiconductor materials during epitaxial growth.

We perform an improved thermodynamic analysis of nonpolar (1 00) and (11 0) surfaces for AlN and GaN to elucidate the difference in growth condition among various types of nonpolar and polar surfaces during metalorganic vapor-phase epitaxy (MOVPE). It is found that the maximum growth temperature of (1 00) surface is lower than those of (0001) and (000 ) surfaces. In contrast, the maximum growth temperature of (11 0) surface is high compared to that of (0001) surface. This orientation dependence corresponds to the relative stability between polar and nonpolar reconstructed surfaces. These results offer a way to provide the optimum growth conditions of AlN and GaN for the MOVPE.