2023/04/25 by Md Hanif Ali, Ali, Md Hanif, Adityanarayan H. Pandey +11
Engineering · Materials Science · #FOS: Physical sciences #Ferroelectric and Negative Capacitance Devices #Machine Learning in Materials Science #Materials Science (cond-mat.mtrl-sci) #Semiconductor materials and devices
paper · pdf · doi:10.48550/arxiv.2304.12924
openalex publication_date 2023/04/25 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Ferroelectricity in sputtered undoped-HfO2 is attractive for composition control for low power and non-volatile memory and logic applications. Unlike doped HfO2, evolution of ferroelectricity with annealing and film thickness effect in sputter deposited undoped HfO2 on Si is not yet reported. In present study, we have demonstrated the impact of post metallization annealing temperature and film thickness on ferroelectric properties in dopant-free sputtered HfO2 on Si-substrate. A rich correlation of polarization with phase, lattice constant, and crystallite size and interface reaction is observed. First, anneal temperature shows o-phase saturation beyond 600 oC followed by interface reaction beyond 700 oC to show an optimal temperature window on 600-700 oC. Second, thickness study at the optimal temperature window shows an alluring o-phase crystallite scaling with thickness till a critical thickness of 20 nm indicating that the films are completely o-phase. However, the lattice constants (volume) are high in the 15-20 nm thickness range which correlates with the enhanced value of 2Pr. Beyond 20 nm, crystallite scaling with thickness saturates with the correlated appearance of m-phase and reduction in 2Pr. The optimal thickness-temperature window range of 15-20 nm films annealed at 600-700 oC show 2Pr of ~35.5 micro-C/cm2 is comparable to state-of-the-art. The robust wakeup-free endurance of ~10^8 cycles showcased in the promising temperature-thickness window has been identified systematically for non-volatile memory applications.