Nondestructive analysis of threading dislocations in GaN by electron channeling contrast imaging

Abstract

Threading dislocations in metal-organic chemical-vapor grown GaN films were imaged nondestructively by the electron channeling contrast imaging (ECCI) technique. Comparisons between ECCI and cross-sectional transmission electron microscopy indicated that pure edge dislocations can be imaged in GaN by ECCI. Total threading dislocation densities were measured by ECCI for various GaN films on engineered 4H-SiC surfaces and ranged from 107to109cm−2. A comparison between the ultraviolet electroluminescent output measured at 380nm and the total dislocation density as measured by ECCI revealed an inverse logarithmic dependence.