Microfocus HRXRD analysis of InP based photonic integrated circuits

Recent improvements in structural characterization by high resolution x-ray diffraction (HRXRD) are reported on Photonic Integrated Circuit (PIC) heterostructures grown on InP substrates. A new diffractometer, providing a sub-millimeter x-ray spot and allowing accurate lateral positioning on the sample, was tested. We compared two set of samples: (i) one is the as-grown material deposited on the complete wafer; (ii) the other one is the same set of samples after different technological processes, leading therefore to very small volume of material localized at specific places on cleaved wafers or chips. We show that with this new tool, useful structural information is still accessible after processes and can lead to further device improvement.