Dislocation analysis of epitaxial InAsSb on a metamorphic graded layer using x-ray topography

Dislocations in compositionally graded virtual substrates and InAsSb epitaxial layers for long wavelength (8–12 μm) photodetectors have been investigated with high-resolution x-ray topography (XRT). By varying the imaging conditions, properties of substrate could be individually characterized. We observe formation misfit dislocations near interface predominantly along (110) direction less relaxation (1–10) direction. The do not form a uniform array but rather appear as dislocation bundles. Threading clusters, which limit device performance, are observed arrays density ∼1 × 105 cm−2 total averaged than 1 106 cm−2. prospects using XRT further optimization development low defect bulk discussed.