Using Hard X-ray photoelectron spectroscopy to study a SiO₂/HfO₂– based interface-dipole-modulation stack embedded in a metal-insulator-metal structure

Abstract Hard X-ray photoelectron spectroscopy was used to examine the interface dipole modulation of SiO2/1-monolayer titanium oxide/HfO2 stack embedded in a metal-insulator-metal structure. Reversible shifts in the Si 1s, Hf 3d, and Ti 1s photoelectron peaks were induced by electrical stress, and they indicate switching of the potential profile inside the SiO2/titanium oxide/HfO2 stack. Moreover, a proportion change in the Ti3+ component of the stack correlates with the potential switching, and that correlation suggests that the structural change around the interface titanium atoms leads to the interface dipole modulation.