Nano to microscale investigation of strain in AlGaN microdisk by 5D X-ray diffraction microscopy

The aim of this proposal is to investigate and demonstrate the high elastic compliance of Al0.15Ga0.85N microdisk from the nanometer to the microscale. We will acquire high spatial resolution imaging of the full tensors of strain and lattice orientation for three different AlGaN/GaN based microstructures: 1) a Al0.15Ga0.85N/GaN micropillar, 2) an Al0.15Ga0.85N microdisk supported by a GaN pillar and 3) the same Al0.15Ga0.85N microdisks above which an AlGaN layer with a higher Al composition has been grown. We demonstrated experimentally, by probing an array of microstructures (mm2), the ability of the thin Al0.15Ga0.85N microdisks to accommodate strain and aim here to quantify it with high spatial resolution in order to understand how the deformation of the Al0.15Ga0.85N microdisk takes place across the fabrication process. A second set of experiment will also be performed using a 20 µm beamsize in order to probe a full individual microstructure at various location of the array.