Nanoscale Mapping of the Full Strain Tensor, Rotation, and Composition in Partially Relaxed <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"><mml:msub><mml:mi>In</mml:mi><mml:mi>x</mml:mi></mml:msub><mml:msub><mml:mi>Ga</mml:mi><mml:mrow><mml:mn>1</mml:mn><mml:mo>−</mml:mo><mml:mi>x</mml:mi></mml:mrow></mml:msub><mml:mi mathvariant="normal">N</mml:mi></mml:math> Layers by Scanning X-ray Diffraction Microscopy
Carsten Richter, Vladimir M. Kaganer, Armelle Even, A. Dussaigne, P. Ferret, Frédéric Barbier, Yves-Matthieu Le Vaillant, Tobias U. Schülli
Abstract
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 demonstrate 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 ${\mathrm{In}}_{x}{\mathrm{Ga}}_{1\ensuremath{-}x}\mathrm{N}$ double layer to study strain relaxation and indium incorporation phenomena. The contributions due to varying indium content and threading dislocations are separated and analyzed.