The effect was reported of controlled growth dynamics, as monitored by in situ optical reflectance, on the microstructure of non-polar a-plane GaN films grown onto r-plane sapphire. The mosaic microstructure of the a-plane GaN and its anisotropy were evaluated using X-ray rocking curve measurements. By inserting an islanding stage, followed by enhanced lateral growth, pit-free a-plane GaN was obtained with an X-ray rocking curve linewidth of ∼0.18 and ∼0.3° for on- and off-axis planes, respectively; with only minor anisotropy. The density of basal-plane stacking faults was reduced by some 70%, as determined by using a modified Williamson–Hall X-ray analysis.

Effect of Controlled Growth Dynamics on the Microstructure of Nonpolar a-Plane GaN Revealed by X-ray Diffraction. Q.Sun, T.S.Ko, C.D.Yerino, Y.Zhang, I.H.Lee, J.Han, T.C.Lu, H.C.Kuo, S.C.Wang: Japanese Journal of Applied Physics, 2009, 48[7], 071002