Achieving a Record-High Capacitive Energy Density on Si with Columnar Nanograined Ferroelectric Films
Hanfei Zhu, Yuyao Zhao, Jun Ouyang, Kun Wang, Hongbo Cheng, Yu Su
Abstract
High energy density dielectric film capacitors are desirable in modern electronic devices. Their miniaturization and integration into Si-based microsystems create opportunities for in-circuit energy supply, buffering, and conditioning. Here, we present a CMOS (complementary metal oxide semiconductor)-compatible route for the fabrication of BaTiO3 film capacitors on Si with a record-high recoverable energy density and good efficiency (∼242 J/cm3 and ∼76% at 8.75 MV/cm). These BaTiO3 films were sputter-deposited at 350 °C and consisted of slightly compressed superfine columnar nanograins with a (001) texture. Such a nanostructure was endowed with a high breakdown strength, a reduced remnant polarization, and an enhanced maximum polarization, which are accountable for their excellent energy storage performance. Moreover, these BaTiO3 film capacitors displayed a high electrical fatigue resistance, a wide range of operating temperatures, and an excellent frequency stability. With an engineered nanostructure, the prototype perovskite of BaTiO3 has shown great promise for capacitive energy storage applications.