The planar anodic Al₂O₃-ZrO₂ nanocomposite capacitor dielectrics for advanced passive device integration

The need for integrated passive devices (IPDs) emerges from the increasing consumer demand for electronic product miniaturization. Metal-insulator-metal (MIM) capacitors are vital components of IPD systems. Developing new materials and technologies is essential for advancing capacitor characteristics and co-integrating with other electronic passives. Here we present an innovative electrochemical technology joined with the sputter-deposition of Al and Zr layers to synthesize novel planar nanocomposite metal-oxide dielectrics consisting of ZrO₂ nanorods self-embedded into the nanoporous Al₂O₃ matrix such that its pores are entirely filled with zirconium oxide. The technology is utilized in MIM capacitors characterized by modern surface and interface analysis techniques and electrical measurements. In the 95–480 nm thickness range, the best-achieved MIM device characteristics are the one-layer capacitance density of 112 nF·cm⁻², the loss tangent of 4·10⁻³ at frequencies up to 1 MHz, the leakage current density of 40 pA·cm⁻², the breakdown field strength of up to 10 MV·cm⁻¹, the energy density of 100 J·cm⁻³, the quadratic voltage coefficient of capacitance of 4 ppm·V⁻², and the temperature coefficient of capacitance of 480 ppm·K⁻¹ at 293–423 K at 1 MHz. The outstanding performance, stability, and tunable capacitors’ characteristics allow for their application in low-pass filters, coupling/decoupling/bypass circuits, RC oscillators, energy-storage devices, ultrafast charge/discharge units, or high-precision analog-to-digital converters. The capacitor technology based on the non-porous planar anodic-oxide dielectrics complements the electrochemical conception of IPDs that combined, until now, the anodized aluminum interconnection, microresistors, and microinductors, all co-related in one system for use in portable electronic devices.集成无源器件（integrated passive devices, IPDs）的需求源于消费者对电子产品小型化的日益增长的诉求。金属-绝缘体-金属（Metal-insulator-metal, MIM）电容器是IPD系统的关键组成部分。研发新型材料与工艺技术，对于优化电容器性能、实现与其他电子无源元件的共集成至关重要。本研究提出一种创新电化学工艺，结合铝（Al）与锆（Zr）层的溅射沉积技术，合成了新型平面纳米复合金属氧化物电介质：二氧化锆（ZrO₂）纳米棒自嵌入纳米多孔氧化铝（Al₂O₃）基体中，且基体孔隙完全被氧化锆填充。该工艺被应用于MIM电容器的制备，并通过现代表面与界面分析技术及电学测试对其性能进行表征。在95~480 nm的厚度区间内，该MIM器件实现的最优性能参数包括：单层电容密度达112 nF·cm⁻²，1 MHz及以下频率下的损耗角正切为4×10⁻³，漏电流密度为40 pA·cm⁻²，击穿场强最高可达10 MV·cm⁻¹，能量密度为100 J·cm⁻³，1 MHz下293~423 K温度区间内的电容二次电压系数为4 ppm·V⁻²，电容温度系数为480 ppm·K⁻¹。该电容器凭借优异的性能、稳定性以及可调控的特性，可应用于低通滤波器、耦合/去耦/旁路电路、RC振荡器、储能器件、超快充放电单元以及高精度模数转换器等场景。基于无孔平面阳极氧化电介质的电容器工艺，进一步完善了IPDs的电化学设计框架——迄今为止，IPD的电化学设计仅将阳极氧化铝互连结构、微电阻器与微电感器整合为单一系统，用于便携式电子设备。