Enhancing ferroelectric performance in hafnia-based MFIS capacitor through interface passivation and bulk doping

Area of Science:

• Materials Science
• Solid State Physics
• Nanotechnology

Background:

• Hafnia (HfO2)-based ferroelectrics are crucial for advanced electronics due to their CMOS compatibility and thin-film ferroelectric properties.
• Enhancing ferroelectric characteristics and durability of HfO2 films is essential for high-performance non-volatile memory applications.

Purpose of the Study:

• To improve the ferroelectric performance and endurance of HfₓZr₁₋ₓO₂(HZO) films on silicon substrates.
• To investigate the role of oxygen vacancies (V<0xE1><0xB5><0xA2>) in HZO ferroelectric properties.

Main Methods:

• Engineered oxygen vacancies in HfₓZr₁₋ₓO₂(HZO) films through a dual approach.
• Incorporated an Al₂O₃ interlayer to reduce interfacial oxygen vacancies.
• Introduced Al dopants into the HZO film to increase bulk oxygen vacancy concentration.

Main Results:

• Achieved a significant enhancement in ferroelectric performance with a remanent polarization (2Pr) of 47 μC cm⁻².
• Demonstrated remarkable endurance, withstanding up to 10⁸ cycles at 8 MV cm⁻¹ without a wake-up process.
• Attributed improvements to the modulation of oxygen vacancy concentration, facilitating the ferroelectric o-III phase.

Conclusions:

• The proposed strategy effectively enhances the ferroelectric properties of HfO₂-based materials.
• This method offers a viable alternative for improving ferroelectricity in fluorite crystal structured materials.
• Optimized oxygen vacancy engineering is key for next-generation ferroelectric memory devices.