Correlation between current leakage and structural properties of threading dislocations in GaN bulk single crystals grown using a Na-flux method

What is it about?

Electrical and microstructural properties of threading dislocations (TDs) in Na-flux-grown GaN bulk single crystals composed of c-plane growth sector (cGS) were investigated using C-AFM, MPPL (multi-photon photo luminescence) and TEM. We found that bundled a-type or a+c type dislocations show larger leakage current and correlation between etch-pit size (strain-field strength) and leakage current was observed.

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Photo by Axel Richter on Unsplash

Photo by Axel Richter on Unsplash

Why is it important?

Gallium nitride (GaN) is a promising wide-gap semiconductor material for next generation high-power electronic devices such as Schottky barrier diodes or MOSFETs. For its practical application the suppression of electrical degradation due to dislocations is crucial. The combined C-AFM and MPPL analysis revealed that leakage currents increase at TDs located in micro-facet growth sectors with high oxygen impurity content and at bundled a-type or a+c type TDs with higher strain fields. Dislocation strain fields can promote interaction with oxygen impurity and affect electrical characteristics such as reverse leakage. These findings will contribute to the development of power electronic devices with improved efficiency and reliability.