Operando hard X-ray photoelectron spectroscopy study of the Pt/Ru/PbZr$_{0.52}$Ti$_{0.48}$O$_3$ interface

Abstract : We have used hard X-ray photoelectron spectroscopy to probe the Pt/Ru/PbZr$_{0.52}$Ti${0.48}$O$_3$ (PZT) interface in a Pt/Ru/PZT(220 nm)/Pt/TiO$_2$/SiO$_2$/Si stack. A customized sample-holder allows in-situ photoemission analysis while applying bias to the capacitor. Hard X-rays probe the buried interface between the top electrode and the ferroelectric PZT. The use of operando conditions reveals a polarization-dependent electronic response, most probably due to imperfect screening of the depolarizing field. There is evidence for an additional core level component related to the electrode-PZT interface. Zr oxide nanostructures at the surface of the sol-gel layer may form a ferroelectric dead layer at the interface, affecting device performance.