Secondary Ions Mass Spectrometry detection of oxygen impurities in gallium nitride
Futher development of GaN-based optoelectronic devices requires in-depth understanding of the defects present in GaN grown on a sapphire substrate. Left: 3D view of oxygen counts in a 5 µm x 5 µm x 1 µm cuboid. Oxygen agglomerates along the pillar-shaped structures. Right: Lateral distribution of oxygen secondary ions (blue pixels) projected on a SEM micrograph of wet etched gallium nitride. A clear correlation between the position of the largest pits and oxygen shows that screw and mixed dislocations have a high tendency to be decorated by oxygen.
Recorded on CAMECA SC Ultra at Łukasiewicz Research Network - Institute of Microelectronics and Photonics, Warsaw, Poland. Image courtesy of P. Michałowski.
P. Michałowski et al. Three dimensional localization of unintentional oxygen impurities in gallium nitride. Chemical Communications, vol. 55, 11539-11542, (2019).