Passive components support key electrical functions in any electronic system. They constitute ~80% of all components [1] and take up to ~50% of the printed wiring board area [2]. They, therefore, substantially influence the size, cost, and performance of the electronic system as a whole. Capacitors (C) are the most challenging among all the passives (R, L, and C). They perform a multitude of important functions such as decoupling, noise suppression, power storage conditioning and modulation, sensing, and signal processing. The never-ending demand for the high-performance, portable electronics has propelled the need for miniaturization of electronic components, including the capacitors. This demand for miniaturization entails the fabrication of thin power modules that are less than 200 µm in thickness to be embedded into 3D silicon and organic packages [3]. Additionally, these packages need to be reliably and safely operated over a broad temperature range [4]. So far, these passive components, especially the capacitors, have been major impediments on the road to system miniaturization and thickness reduction. Although the demand for high-density capacitors in integrated thin power modules has been increasing, the volumetric density of the available discrete capacitors has only gone through incremental changes over the past few decades. This is because of several fundamental limitations with existing capacitor technologies. Today’s high-density capacitors face the imminent demand of ultrahigh volumetric densities, ultralow leakage currents, high-frequency operation, and faster charge-discharge speeds. The current capacitor technologies are stretching their limits to explore novel materials, processes, and integration methods to meet the demands, but suffer from several fundamental limitations. A new class of nanocapacitor technologies is needed to address these limitations, which is the main focus of this chapter.
