Unveiling the influence of selective-area-regrowth interfaces on local electronic properties of GaN p-n junctions for efficient power devices

We report correlated nanoscale mapping of the structure, composition, and properties regrown GaN p-n junctions to identify how etching non-planar regrowth processes limit diode performance via introduction unintentional dopants defect states. p-GaN was selectively in n-GaN trenches with SiO2 masks variable mask-to-trench-width ratio. Dilute Al layers were periodically introduced during as markers growth interface. Correlated doping, conductivity, dopant complexes achieved atom probe tomography (APT), scanning spreading resistance microscopy (SSRM), cathodoluminescence (CL) spectroscopy, respectively. The marker layers, detected by APT, enabled reconstruction faceted interface correlation concentration position time. rate is proportional mask-to-trench width ratio while incorporation invariant. At trench edges, magnesium suppressed, oxygen enhanced, due preferential on semi-polar surface, leading compensation less abrupt junctions; mask a source oxygen. Residual etch damage below induces n-type p-type creating leakage pathways. non-uniform Mg driven crystal anisotropy thus inherent regrowth, but can be mitigated engineering process parameters. unprecedented integration spatially resolved dopants, impurities, carrier type powerful approach discriminating distinct factors that diodes, enabling rational optimization device design.