Highly reliable ferroelectricity of HfO2–TiO2 nanolaminates thin films grown by plasma-enhanced atomic layer deposition

Abstract

Ferroelectric materials are gaining significant attention as next-generation semiconductor devices due to their unique properties. In this study, we developed HfO2–TiO2 (HTO) nanolaminates using PEALD method and investigated their film structure and ferroelectric performance. GIXRD analysis revealed the presence of the HTO orthorhombic phase, TiO2 anatase phase, and β-W phase in the nanolaminate films after annealing. Electrical characterization revealed a leakage current density of 9.45 × 10–7 A/cm2 at applied voltage of 1 V, which is close to the current industry standard for gate oxides. The P–V hysteresis loops exhibited a maximum remanent polarization of 4.65 μC/cm2, underscoring the tunable ferroelectric and electrical properties of HTO nanolaminates achieved by carefully controlling the deposition sequence and post-deposition annealing. It is found that the C–V measurements indicated a dielectric constant (k) ranging from 32 to 33 over a frequency range of 10 kHz to 1 MHz, suggesting its viability as a high-k dielectric material in advanced semiconductor application. Additionally, the endurance tests showed remarkable stability, withstanding up to 107 cycles. This study optimizes the process parameters for fabricating ferroelectric HTO thin films using PEALD and highlights their potential applications in ferroelectric-based devices.