Enhancement of electrical properties of morphotropic phase boundary in Hf1-xZrxO2 films by integrating Mo electrode and TiN interlayer for DRAM capacitors
Ju Yong Park, Hyojun Choi, Jaewook Lee, Kun Yang, Sun Young Lee, Dong Han, Intak Jeon, Chang Hwa Jung, Hanjin Lim, Woongkyu Lee, Min Hyuk Park
Abstract
Molybdenum is considered a promising electrode material for Hf 1-x Zr x O 2 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 Hf 1-x Zr x O 2 -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 Hf 1-x Zr x O 2 films, as confirmed by transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) studies. An optimized 6 nm-thick Hf 0.3 Zr 0.7 O 2 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 (DRAM).