Control of dislocations and stress in AlGaN on sapphire using a low temperature interlayer

In organometallic vapor phase epitaxial growth of AlGaN on sapphire, the ro le of the low-temperature-deposited interlayers on a high-temperature-grown GaN layer was investigated by in-situ stress measurement, X-ray diffractio n, and transmission electron microscopy. Crack-free and low-dislocation-den sity AlGaN with the whole compositional range has been realized on the sapp hire substrate.