Ultra-high pressure annealing of Mn-implanted HVPE-GaN

Manganese diffusion in ion implanted gallium nitride crystals was investigated. The ions were implanted into a sample composed of a GaN layer grown using halide vapor phase epitaxy on an ammonothermal gallium nitride substrate. The sample was polished into an atomically flat state prior to the implantation. Manganese ions were implanted into the surface of a (0001) plane (also known as the c-plane) using the beam energy of 230 keV and ion fluence of 5E15 cm−2. The beam was tilted relative to the sample's normal to prevent channeling. After the implantation, ultra-high pressure annealing method was used to both, remove the post-implantation damage and induce the diffusion of implanted Mn ions. Manganese profiles were analyzed along the c-direction using secondary ion mass spectrometry after 5 and 30 h of annealing in temperatures ranging from 1473 K to 1753 K. Two diffusion mechanisms were observed. The diffusion parameters, activation energy and temperature-independent diffusion coefficients, are presented for each mechanism. Additionally, the structural quality of the samples is assessed after 5 and 30-hour annealing in the aforementioned temperature range through the means of X-ray diffractometry.