Impact of high-temperature growth by metal-organic vapor phase epitaxy on microstructure of AlN on 6H-SiC substrates

We investigated impact of high-temperature growth by metal-organic vapor phase epitaxy on crystallographic quality of AlN on 6H-SiC (0 0 0 1) Si substrate. With increasing growth temperature ( T g), growth rate became high and residual impurities decreased. For T g=1600 °C, AlN with atomically flat surface and low dislocation density were reproducibly obtained under the high growth rate at 6 μm/h. The narrowest distribution of tilt and twist were 76 and 360 arcsec, respectively, and the average dislocation density was measured to be 7×10 8 cm −2. Most of dislocations were of edge-type, generated by the misfit between the AlN and the SiC substrate. For increases of T g up to 1600 °C, the number of dislocations at AlN/SiC interface decreased, and many of the dislocations were annihilated by the formation of a loop structure.