Low-Temperature Plasma-Induced Oxygen-Vacancy Engineering Enables Orthorhombic-Phase Stabilization in Hf0.5Zr0.5O2 for 2D FeFETs toward Monolithic 3D Integration

Abstract

Abstract The rapid growth in artificial intelligence and large-scale data processing has driven the urgent demand for energy-efficient electronic devices. Ferroelectric materials, especially hafnium zirconium oxide (Hf0.5Zr0.5O2, HZO), have emerged as promising candidates due to their inherent nonvolatile polarization and complementary metal–oxide–semiconductor compatibility at nanoscale thicknesses. However, conventional high-temperature annealing (>400 °C) limits integration with temperature-sensitive and two-dimensional (2D) semiconductor platforms such as MoS2. Here, we demonstrate a low-temperature (∼300 °C) plasma-induced crystallization strategy that stabilizes the orthorhombic phase in sputtered HZO films through plasma-induced modification of the oxygen-deficient defect configuration. This approach enables direct integration of ferroelectric HZO with bilayer MoS2, integrating top-gate ferroelectric field-effect transistors (FeFETs) that exhibit robust polarization switching, a large memory window, on/off ratios exceeding 106, reliable device-to-device uniformity, and long-term retention with projected stability beyond 10 years. The ability to induce ferroelectric phase formation at lower thermal budgets highlights the compatibility of plasma-processed HZO with 2D materials and back-end-of-line constraints. This work establishes a potential pathway toward monolithic 3D integration and advances the development of energy-efficient nonvolatile memory, neuromorphic hardware, and reconfigurable logic based on hybrid 2D ferroelectric device architectures.