Ion channeling studies on mixed phases formed in MOCVD grown Mg-doped GaN on Al/sub 2/O/sub 3/ (0001)

Rutherford backscattering spectrometry (RBS) and channeling is used to determine the presence of wurtzite and zinc-blende phases of MOCVD grown Mg-doped GaN(0001) on Al/sub 2/O/sub 3/(0001) substrate with GaN buffer layer from the off-normal axial scans and is complemented with high resolution X-ray diffraction measurements. The in-plane orientation of wurtzite phase is found to be GaN [101~0]/spl par/A1/sub 2/O/sub 3/[101~0]. Presence of stacking faults and dislocations at different depths are observed in the GaN epilayer. The effects of rapid thermal annealing (RTA) on the phase contents, thickness and crystalline quality of GaN epilayer are also studied.