X-ray standing wave photoemission from multilayer nanostructures

We have used soft and hard x-ray standing wave excitation of photoelectrons to study buried layers and interfaces in multilayer nanostructures. The samples were grown on synthetic multilayer mirrors, and the x-ray incidence was tuned to 1$^{st}$ order Bragg reflection. Scanning angle, photon energy, or distance along a wedge profile in the sample permits scanning the resultant standing wave field through nm-scale structures and analyzing the depth distribution of their chemical, electronic, magnetic, and structural properties. Using harder x-ray excitation permits via the higher kinetic energy of the electrons studying those properties at greater depths. The systems discussed will be two related to magnetic tunnel junctions (magnesium oxide/iron and STO/LSMO), and one related to integrated circuit production (titanium nitride on silicon).