Microstructure of GaN Heteroepitaxial Layers after Diffusion of Mg, Zn and Au under High Pressure

摘要

Transmission electron microscopy was used to study the defects generated in GaN heteroepitaxial layers during diffusion of Au, Zn and Mg in the temperature range 900℃ - 1200℃. The diffusion annealings were carried out under N2 pressure of 1 GPa in order to avoid decomposition of GaN. Diffusion of the metals into the GaN layers was connected with formation of voids and nanotubes along dislocation cores. The penetration profiles were measured by means of SIMS. The effective diffusion coefficients and the activation energy for Au diffusion in GaN were calculated.