Enhancement of electrical properties of morphotropic phase boundary in Hf1-xZrxO2 films by integrating Mo electrode and TiN interlayer for DRAM capacitors

Mo is considered a promising electrode material for Hf1-xZrxO2 films owing to its enhancing impact on ferroelectricity and dielectric constant. However, it poses significant limitations, such as high leakage current density and low endurance, which must be addressed to ensure its applicability in Hf1-xZrxO2-based memories. The insertion of a TiN interlayer has been proven to effectively reduce the oxidation of a Mo electrode and suppress the formation of oxygen vacancies in Hf1-xZrxO2 films, as confirmed from transmission electron microscopy and X-ray photoelectron spectroscopy studies. An optimized 6 nm-thick Hf0.3­Zr0.7O2 film with a TiN interlayer exhibited a leakage current density below 10-7 A/cm2 at 0.8 V and an equivalent oxide thickness of 0.49 nm, demonstrating its suitability for cell capacitors in dynamic random-access-memories.