Spatially resolved X-ray diffraction measurements on (Al,Ga)N/GaN/4H-SiC heterostructures for electronic devices

Structural defects and their impact on the performance of electronic devices are of permanent interest for crystal growers and device manufacturers. This is especially true for epitaxial (Al,Ga)N/GaN-based high electron mobility transistor structures on 4H-SiC (0 0 0 1) substrates. This work concentrates on the recognition and imaging of defects in (Al,Ga)N/GaN/4H-SiC(0001) heterostructures accomplished non-destructively by three X-ray diffraction techniques. X-ray topography and X-ray Bragg angle mapping are compared with respect to the spatial resolution of the defects. X-ray curvature measurements are used to quantify long-ranging stresses in the heterostructure during device fabrication.