Dislocation reduction in GaN with double Mg_xN_y/AlN buffer layer by metal organic chemical vapor deposition

Unintentionally doped GaN with conventional single low-temperature (LT) AlN buffer layer and with double Mg_xN_y/AlN buffer layers both were prepared. It was found that we could reduce defect density and thus improve crystal quality of the GaN by using double Mg_xN_y/AlN buffer layers. GaN with double Mg_xN_y/AlN buffer layers reveals an asymmetrical reflection (1 0 2) and (0 0 2) with a smaller full-width at half-maximum (FWHM), and a higher mobility, lower background concentration and lower etching pit density (EPD) than the GaN with the LT-AlN buffer layer.