Nanoscale Mapping of the Full Strain Tensor, Rotation, and Composition in Partially Relaxed InxGa1-xN Layers by Scanning X-ray Diffraction Microscopy

Strain and composition play a fundamental role in semiconductor physics, since they are means to tune the electronic and optical properties of a material and hence develop alternative devices. Today it is still a challenge to measure strain in epitaxial systems in a nondestructive manner, which becomes especially important in strain-engineered devices that often are subjected to intense stress. In this work, we demon-strate a microscopic mapping of the full tensors of strain and lattice orientation by means of scanning x-ray diffraction microscopy. We develop a formalism to extract all components of strain and orientation from a set of scanning diffraction measurements and apply the technique to a patterned InxGa1-xN double layer to study strain relaxation and indium incorporation phenomena. The contributions due to varying indium content and threading dislocations are separated and analyzed.

Automated summary

Strain and composition are important in semiconductor physics, but nondestructive measurement of strain in epitaxial systems remains a challenge. This study demonstrates a microscopic mapping of strain and lattice orientation using scanning x-ray diffraction microscopy and applies it to study strain relaxation and indium incorporation phenomena.