Atomic layer-deposited (HfZrO4)1 − x(SiO2)x thin films for gate stack applications

Highlights: • (HfZrO₄)_1−x(SiO₂)_x dielectric films were developed and characterized. • Thermal stabilities were enhanced with incorporation of SiO₂. • A film with 15% SiO₂ was demonstrated to be a high dielectric constant candidate. - Abstract: Hafnium‑zirconium silicate (HfZr-silicate, (HfZrO₄)_1−x(SiO₂)_x) thin films were developed for advanced gate stack applications by incorporating Si atoms into virgin hafnium‑zirconium oxide (HfZrO₄) via atomic-layer deposition, yielding films with varying Si content (x = 0.10, 0.15, and 0.20). Electron conduction behavior was responsible for a reduction in the gate leakage current of HfZr-silicate compared to pure HfZrO₄ films and was clearly explained by a conduction-electron generation model. Furthermore, HfZr-silicate-based structures exhibited less charge trapping and featured improved interfacial stability when in contact with Si substrate compared to virgin HfZrO₄, although they both experienced bias and thermal stress. These phenomena were associated with the formation of an interfacial layer (IL) between virgin HfZrO₄ and the Si substrate, while there was no IL for the HfZr-silicate. With regard to the electrical properties of the films with varying Si incorporation, film with 15% SiO₂ was recommended as a high dielectric constant candidate due to its superior electrical properties and outstanding durability.