Quantitative nanoscale imaging of lattice distortions in epitaxial semiconductor heterostructures using nanofocused X-ray Bragg projection ptychography.

We imaged nanoscale lattice strain in a multilayer semiconductor device prototype with a new X-ray technique, nanofocused Bragg projection ptychography. Applying this technique to the epitaxial stressor layer of a SiGe-on-SOI structure, we measured the internal lattice behavior in a targeted region of a single device and demonstrated that its internal strain profile consisted of two competing lattice distortions. These results provide the strongest nondestructive test to date of continuum modeling predictions of nanoscale strain distributions.