An AlN microsphere was grown by using a mixed-source hydride vapor phase epitaxy (HVPE) method a reactor and combining the source with the growth regions and a graphite boat prefilled with the mixed source (Ga+Al) in the source region. The custom-designed reactor was designed to minimize reactions between quartz and AlCl vapor species and to reduce the response distance for synthesis for neighboring source and growth zones at a high source-zone temperature of 1150$^{\circ}$C. Field-emission scanning electron microscopy (FE;SEM), electron-energy dispersive spectroscopy (EDS), and field-emission transmission electron microscopy (FE;TEM) were used in order to investigate the characteristics of the AlN microsphere. We discuss the role of Ga in the mixed source in the AlN microsphere growth process and the results of an investigation of the growth mechanism of the AlN microsphere.

Keywords: AlN microspheres, Mixed-source HVPE, micro-puddles, Cubic AlN