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

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 1 s, Hf 3d, and Ti 1 s photoelectron peaks were induced by electrical stress, and they indicate the switching of the potential profile inside the SiO2/titanium oxide/HfO2 stack. Moreover, a proportion change in the Ti3+ component correlates with the potential switching, and that correlation suggests that the structural change around the interface titanium atoms leads to the interface dipole modulation.