Effect of hydrogen derived from oxygen source on low-temperature ferroelectric TiN/Hf_0.5Zr_0.5O₂/TiN capacitors

The ferroelectric (FE) properties of 10-nm-thick Hf_0.5Zr_0.5O₂ (HZO) films deposited by an atomic layer deposition technique were improved by adopting O₃ as an oxygen source instead of H₂O. All HZO films were annealed at 400 °C for 1 min in an N₂ atmosphere after TiN top electrode deposition. Regardless of the oxygen source, the HZO films exhibited the formation of a noncentrosymmetric orthorhombic phase, which is responsible for FE behavior with the suppression of the monoclinic phase. However, compared to the O₃-based HZO film, it was confirmed that the H₂O-based HZO film was more incorporated with hydrogen derived from H₂O, thereby degrading FE polarization and leakage behavior. The results indicate that the strategy of using O₃ as the oxygen source is useful for the fabrication and integration of FE HZO films for next-generation memory applications.