High Energy Performance Ferroelectric (Ba,Sr)(Zr,Ti)O₃ Film Capacitors Integrated on Si at 400 °C

Abstract

BaTiO3-based ferroelectrics have been extensively studied due to their large dielectric constants and a high saturated polarization, which have the potential to store or supply electricity of very high energy and power densities. In order to further improve the energy efficiency η and the recyclable energy density W rec, an A, B-site co-doped (Ba0.95,Sr0.05)­(Zr0.2,Ti0.8)­O3 ceramic target was used for sputter deposition of film capacitor structures on Si. This film composition reduces the remnant polarization P r, while the choice of a low-temperature, templated sputtering process facilitates the formation of high-density arrays of columnar nanograins (average diameter d ∼20 nm) and grain boundary dead layers. This self-assembled nanostructure further delays the saturation of the electric polarization, leading to a high energy density W rec of ∼148 J/cm3 and a high energy efficiency η of ∼90%. Moreover, the (Ba0.95,Sr0.05)­(Zr0.2,Ti0.8)­O3 film capacitors retain their high energy storage performance in a broad range of working temperature (−175–300 °C) and operating frequency (1 Hz–20 kHz). They are also fatigue-free after up to 2 × 109 switching cycles. Our work provides a new method and a cost-effective processing route for the creation and integration of high-performance dielectric capacitors for energy storage applications.

Achieving a Record-High Capacitive Energy Density on Si with Columnar Nanograined Ferroelectric Films

“…36,37 Moreover, a reduced thickness of the LaNiO 3 buffer layer will limit its grain growth, hence further refining the BaTiO 3 grains through a seeding effect. 29,30 It is noted that the influence of grain size on the P−E loop of the BaTiO 3 film has been demonstrated experimentally, and the result is consistent with the above PFM simulation (Note S2, Figure S2, Supporting Information).…”

Synergistic Optimization in a 0.90BaTiO3–0.08Bi(Ni0.5Zr0.5)O3–0.02BiFeO3 Thin Film with High Breakdown Strength and Energy Density

“…On the one hand, nanometersized polar clusters or columnar nanograins prepared by microstructure design will increase the value of P max −P r and obtain high η under a large electric field. 31 Unfortunately, excessive nanocrystalline will transform into large-scale grains, which will result in irreparable performance degradation due to the increasing P r and decreased BDS. On the other hand, BiFeO 3 is used for modifying polarization performance via defect engineering.…”

“…However, improving the polarization of amorphous thin films can make them have broader application prospects. On the one hand, nanometer-sized polar clusters or columnar nanograins prepared by microstructure design will increase the value of P max – P r and obtain high η under a large electric field . Unfortunately, excessive nanocrystalline will transform into large-scale grains, which will result in irreparable performance degradation due to the increasing P r and decreased BDS.…”

Ultrahigh Temperature Lead‐Free Film Capacitors via Strain and Dielectric Constant Double Gradient Design

“…Energy storage density at room temperature has been greatly improved in recent several years and the highest value has already gone up to 148 J cm –3 . [ 2 ] However, energy storage density at high temperatures is far lower than that at room temperature, limiting the working temperature range of the dielectric capacitors. With the development of device miniaturization, integration and lightweight, it is desirable to extend the working temperature of dielectric capacitors and improve their thermal stability.…”