Investigation of beryllium diffusion in HVPE-GaN grown in [11-20] and [10-10] crystallographic directions

The diffusion of beryllium in gallium nitride crystals grown in non-polar crystallographic directions by halide vapor phase epitaxy was investigated. The layers were crystallized on (10-10) and (11-20) planes of native ammonothermal substrates of the highest structural quality. The new-grown crystals were prepared to an epiready state, implanted with beryllium, and treated with ultra-high-pressure annealing. The crystallographic structure of all the samples before and after ion implantation as well as annealing processes was evaluated by Xray diffraction measurements. The diffusion of beryllium was investigated by analyzing depth profiles obtained by secondary ion mass spectrometry. The diffusion profiles were box-shaped for both examined non-polar directions. Pre-exponential factors and activation energies for beryllium diffusion in non-polar gallium nitride were determined. A model related to point defect complexes, based on gallium vacancies and oxygen, was proposed for explaining the box-shaped beryllium diffusion profiles and the visible differences in the diffusion range between the two analyzed non-polar directions.

Automated summary

The diffusion of beryllium in gallium nitride crystals grown in non-polar crystallographic directions was investigated. The diffusion profiles were found to be box-shaped and pre-exponential factors and activation energies were determined. A model based on point defect complexes was proposed to explain the profiles and visible differences between the two directions.