Thermally Stable Sr₂RuO₄ Electrode for Oxide Heterostructures

Area of Science:

• Materials Science
• Solid State Physics
• Thin Film Deposition

Background:

• Oxide heterostructures are crucial for advanced electronic devices.
• High-temperature synthesis is often required for optimal material properties.
• Thermally stable electrodes are essential for reliable high-temperature fabrication processes.

Purpose of the Study:

• To investigate the thermal stability of strontium ruthenate (Sr$_{2}$RuO$_{4}$) as an electrode material.
• To assess the suitability of Sr$_{2}$RuO$_{4}$ for high-temperature synthesis of ferroelectric heterostructures.
• To determine the optimal growth conditions for ferroelectric films on Sr$_{2}$RuO$_{4}$ electrodes.

Main Methods:

• Pulsed laser deposition (PLD) for growing Sr$_{2}$RuO$_{4}$ thin films on SrTiO$_{3}$(001) substrates.
• Fabrication of ferroelectric Barium Titanate (BaTiO$_{3}$) capacitors using Sr$_{2}$RuO$_{4}$ as a bottom electrode.
• Structural and electrical characterization of BaTiO$_{3}$ films grown at temperatures up to 1000 °C.

Main Results:

• Atomically smooth Sr$_{2}$RuO$_{4}$ films were successfully grown and exhibited high thermal stability.
• Optimal growth temperature for BaTiO$_{3}$ films was determined to be 900 °C.
• BaTiO$_{3}$ films grown on Sr$_{2}$RuO$_{4}$ showed significant spontaneous polarization, dielectric, and pyroelectric responses.

Conclusions:

• Sr$_{2}$RuO$_{4}$ is a suitable electrode material for high-temperature synthesis (up to 1000 °C) of oxide heterostructures.
• The wide processing window (10$^{-6}$ to 10$^{-1}$ Torr O$_{2}$ pressure) for Sr$_{2}$RuO$_{4}$ surpasses that of other common oxide electrodes like SrRuO$_{3}$.
• The use of Sr$_{2}$RuO$_{4}$ expands fabrication possibilities for optimizing oxide electronic devices.