textit -Axis Oriented HZO on Flat Amorphous TiN Achieving High Uniformity, Breakdown Field, Final 2P } , and Endurance

Metal-ferroelectric-metal (MFM) capacitors with flat amorphous TiN are demonstrated to achieve the \textit{c} -axis of orthorhombic phase (o-phase) well-aligned along the deposition direction, uniform electric field, negligible fatigue, and a high remanent polarization (2P _{\text{r}} ) of 62 \mu C/cm ^{\text{2}} . The large lattice misfit between crystalline TiN and Hf _{\text{0.5}} Zr _{\text{0.5}} O _{\text{2}} (HZO) creates a larger barrier to form the o-phase HZO as compared to the amorphous TiN underlayer. Using chemical-mechanical polishing (CMP) can obtain a 0.3 nm roughness flat TiN, measured by atomic force microscopy (AFM). HZO on flat amorphous TiN exhibits a uniform and high breakdown field (E _{\text{BD}} ) of 4.8/ - 5.1 MV/cm for positive/negative voltage. A flat TiN mitigates the formation of oxygen vacancies (V _{\text{o}} ) as compared to the rough TiN due to the weak and uniform electric field with few local extremes in HZO. After 4E12 endurance cycles, the HZO on the flat TiN exhibits a high final 2P _{\text{r}} of 56 \mu C/cm ^{\text{2}} due to small dipole pinning by V _{\text{o}}^{\text{2}+} . This work demonstrates the way to achieve uniformly high 2P _{\text{r}} , large E _{\text{BD}} , and high endurance by the flat amorphous TiN.