Courtesy: Intel
Highlights
- Intel and Intel Foundry researchers demonstrated three promising metal-insulator-metal (MIM) materials delivering intrinsic capacitance density up to 98 femtofarads per square micrometre (fF/μm²), which is significantly higher than the 37 fF/um² intrinsic capacitance density of the material option used in state-of-the-art technology for more efficient chip power delivery.
- Compatible with advanced integrated MIM structures, these technologies deliver leakage well below targets while maintaining stable performance for over 400,000 seconds at elevated temperature, enabling multi-generational improvements without increasing manufacturing complexity.
- These process technology advances aid in the delivery of high performance per watt for chips ranging from data centres to mobile devices, continuing manufacturing efficiency improvements without added fabrication complexity.
Researchers at Intel and Intel Foundry have demonstrated next-generation decoupling capacitor (DCAP) materials that deliver substantial performance improvements for power delivery in advanced computer chips. Presented at the 2025 IEEE International Electron Devices Meeting (IEDM), the breakthrough takes advantage of unique metal-insulator-metal material properties. Ferroelectric hafnium zirconium oxide (HZO) leverages field-dependent dielectric response to achieve 60 to 80 fF/μm², while titanium oxide (TiO) and strontium titanium oxide (STO) reach 80 and 98 fF/μm² through ultra-high dielectric constants — each offering exceptional reliability with minimal voltage dependency.¹ All three materials show negligible capacitance drift over 100,000 seconds, leakage currents much lower than requirements, and 10-year projected breakdown voltages exceeding specifications at 90 degrees Celsius.
These advances have immediate implications for the semiconductor industry and the broader technology sector. Data centres processing artificial intelligence (AI) workloads can maintain high performance per watt longer with higher MIM decap, completing workloads faster while reducing data centre energy consumption and operation costs. Mobile devices benefit from reliable high performance and faster transitions to lower power states, leading to better battery efficiency. High-performance computing (HPC) systems gain processing headroom from a stable supply voltage, enabling maximum frequency for longer durations.
For chip manufacturers, these new capacitor materials offer a path to continue improving power delivery efficiency across multiple technology generations. The materials integrate seamlessly with existing backend manufacturing processes, enabling adoption without major retooling investments. Today’s advanced MIM capacitors often focus on architectural solutions similar to the state-of-the-art Omni MIM used in Intel 18A. Omni MIM has 397 fF/um² capacitance due to its deep-trench and multi-plate structure (see top image). By developing novel oxide materials that integrate seamlessly with these types of structures, the industry can unlock capacitance densities that exceed today’s benchmarks. These technologies help maintain the economic viability of advancing semiconductor manufacturing while meeting the escalating power delivery demands of next-generation processors, accelerators, and systems of chips designs.
The Challenge of Power Delivery in Advanced Chips
As chips pack more transistors into smaller spaces, maintaining stable power delivery grows increasingly difficult. When billions of transistors switch simultaneously, voltage can drop momentarily — called voltage droop — causing processors to slow, make errors, or run at reduced speeds. Decoupling capacitors solve this issue by acting as electrical reservoirs that instantly supply current when needed and absorb excess when demand drops.
Traditional approaches to increasing capacitance involve stacking multiple capacitor layers or etching deeper trenches to create more surface area. However, both significantly increase manufacturing complexity and cost. Material innovations offer an alternative by dramatically increasing the effective dielectric response, which is the material’s ability to store electrical charge. Finding materials with high effective dielectric constants that meet strict reliability requirements for years of operation at elevated temperatures represents a major materials science challenge.
Harnessing Ferroelectric Materials for Voltage-Responsive Capacitance
Ferroelectric hafnium zirconium oxide offers a unique property — the ability to store electrical charge changes with the applied electric field. Unlike conventional dielectrics, where this ability remains constant, ferroelectric materials contain microscopic regions called domains that orient themselves in response to electric fields, enabling different capacitance values at various operating voltages.
Figure 1. Transmission electron microscope image showing the deep-trench capacitor structure used to characterise the MIM stacks.
This type of testing requires careful attention to measurement methods. Under actual decoupling capacitor operation, where a constant bias voltage experiences small disturbances, the material shows remarkably stable capacitance independent of disturbance voltage, hold time, or number of pulses applied. The ferroelectric capacitors deliver 60 to 80 fF/μm² depending on operating voltage. Extensive reliability testing under various voltage levels, elevated temperatures of 90 degrees Celsius, and extended operation exceeding 400,000 seconds demonstrated negligible capacitance drift.
Figure 2. Capacitance measurements showing HZO’s stable, reliable performance under actual decoupling capacitor usage conditions.
Achieving Ultra-High Capacitance with Advanced Dielectric Materials
Titanium oxide and strontium titanium oxide provide even higher capacitance through extremely high dielectric constants with minimal voltage dependency. TiO achieves approximately 80 fF/μm², while STO reaches 98 fF/μm² — the highest demonstrated capacitance density.
Figure 3. Capacitance versus voltage measurements showing weak voltage dependency across the operating range of interest.
Achieving these performance levels requires precise control over material structure at the atomic scale. The team developed optimised processes, including templating layers that guide crystal growth, controlling film deposition, thermal annealing that promotes desired crystal structure, and interface engineering to minimise defects. X-ray diffraction confirmed the successful production of strong high-dielectric-constant phases in both materials.
For TiO, detailed analysis reveals leakage current follows the Poole-Frenkel mechanism, where electrons trapped at defects gain energy from the electric field and hop between trap sites. This explains why the material withstands high currents without breaking down, with stress-induced leakage behaviour providing self-limiting protection against premature failure.
Exceptional Reliability Enables Multi-Layer Integration
All three materials demonstrate reliability exceeding decoupling capacitor requirements. Leakage current remains below targets even at 90 degrees Celsius. This is achieved through improved dielectric properties rather than making insulators thinner, which would increase leakage.
Time-dependent dielectric breakdown testing stressed devices at higher voltages and elevated temperatures, using statistical models to extrapolate expected lifetime. For HZO, extrapolation predicts operation exceeding high-voltage target spec for 10 years at 90 degrees Celsius with nearly identical breakdown behaviour regardless of voltage polarity. TiO also shows an extrapolated 10-year operating voltage significantly exceeding high-voltage requirements.¹ STO passes reliability targets for lower-voltage applications, though with larger variation due to deposition tooling requiring further optimisation.
The symmetric breakdown behaviour of HZO enables cost-effective multi-layer stacking where multiple capacitor layers connect in series, multiplying total capacitance without requiring complex integration schemes.
Looking Forward: Enabling Next-Generation Computing
This research demonstrates a clear path for continuous decoupling capacitor improvements across multiple semiconductor generations without increasing integration complexity. By improving intrinsic material properties rather than relying on structural innovations like deeper trenches or more layers, these approaches maintain manufacturing feasibility while delivering substantial performance gains.
The three materials provide flexibility for different requirements. HZO offers a practical, near-term option with reliability and straightforward integration. TiO serves as a successor with higher capacitance and exceptional high-voltage capability. STO represents the ultimate capacitance density for applications prioritising maximum capacitance.
Future work will focus on optimising these materials for manufacturing integration, refining deposition processes to improve uniformity, and exploring multi-layer stacking strategies. As computing advances toward AI accelerators, high-performance processors, and energy-efficient data centres, these capacitor technologies will play a vital role in enabling stable power delivery for next-generation semiconductor devices.
