Giant energy storage and power density negative capacitance superlattices

Area of Science:

• Materials Science and Engineering
• Solid State Physics
• Electrical Engineering

Background:

• Dielectric electrostatic capacitors offer ultrafast charge-discharge for high-power energy storage.
• On-chip integration of miniaturized energy storage is crucial for autonomous microelectronics.
• Existing micro-supercapacitors and microbatteries face challenges hindering on-chip integration.

Purpose of the Study:

• To report record electrostatic energy storage density (ESD) and power density in HfO2-ZrO2 thin film microcapacitors.
• To enable on-chip integration for advanced microelectronics and microsystems.
• To overcome the traditional energy storage capacity-speed trade-off.

Main Methods:

• Engineered atomic-layer-deposited antiferroelectric HfO2-ZrO2 films near a field-driven ferroelectric phase transition to utilize the negative capacitance effect.
• Employed antiferroelectric superlattice engineering to enhance energy storage beyond conventional thickness limits.
• Conformally integrated superlattices into three-dimensional capacitors for increased storage per footprint.

Main Results:

• Achieved volumetric ESD beyond state-of-the-art back-end-of-the-line-compatible dielectrics (115 J cm⁻³).
• Boosted areal ESD nine times and areal power density 170 times compared to state-of-the-art electrostatic capacitors (80 mJ cm⁻² and 300 kW cm⁻²).
• Demonstrated monolithic integration of on-chip microcapacitors using a back-end-of-the-line-compatible process.

Conclusions:

• The developed HfO2-ZrO2 microcapacitors achieve unprecedented energy and power densities, overcoming the capacity-speed trade-off.
• This technology enables monolithic integration of high-performance microcapacitors for electronic microsystems.
• The findings pave the way for advanced autonomous microelectronics and microsystems requiring compact, high-power energy storage.