(001)‐oriented BiFeO₃ films integrated on Si with enhanced electrical performances

Abstract

Highly (001)‐oriented pure‐phase BFO films were prepared on traditional Si substrates via radio frequency magnetron sputtering (RFMS). The crystallinity of the films is found to be increased, that is, higher degree of (001) texture, larger grain size, less grain boundary, denser surface morphology, and better thickness uniformity, with increased film thickness. These factors have significant influences on the electrical properties of BFO films, that is, dielectric response, as well as ferroelectric polarization and leakage current characteristics. The 240‐nm‐thick film exhibits relatively poor electrical properties compared with other three thicker films, which is mainly due to its small grain, the enhancement of the clamping effect of neighboring grains, and the absence of domain walls. The essential roles of the evolution and distribution of grains/domains and defect charges in leakage mechanism and ferroelectric switching polarization were also investigated systematically. It was found that 600‐nm‐thick BFO film has the lowest leakage current density (as low as 1.8 × 10−6 A / cm2 @ 90 kV/cm) and followed a mixed SE or SCLC conduction behavior, while the leakage behavior in other films is dominated by SE and P‐F currents. All (001)‐BFO films have a giant electrical polarization which is solely originated from the contribution of ferroelectric domain switching, and it has lower switching voltage and faster switching rate in thicker films.

Outstanding Ferroelectricity in Sol–Gel-Derived Polycrystalline BiFeO3 Films within a Wide Thickness Range

“…Comparison of ferroelectric properties of pure-phase BiFeO 3 films with reported achievable large polarizations: (a) films obtained by the sol–gel method (green ■: epitaxial and textured films; − red ● and magenta ●: polycrystalline films from the literature ,− and evaluated in this study, respectively); (b) films fabricated by physical deposition methods (green ■, dark green ■, and light green ■: epitaxial and textured films by PLD, − rf magnetron sputtering, − and MBE methods; red ●: polycrystalline films − ).…”

Alternating Spin-Coating Sol–Gel Synthetic Route for Highly (100)-Textured Potassium Sodium Niobate Films

“…Therefore, we fabricated these two entirely different types of BEs and investigated their effects on the crystalline structure and electrical performance of KNN films synthesized by different routes. The deposition of LNO and Pt/Ti electrodes on Si substrates was accomplished through radio-frequency magnetron sputtering, and the process parameters can be found elsewhere. , …”

“…The deposition of LNO and Pt/Ti electrodes on Si substrates was accomplished through radio-frequency magnetron sputtering, and the process parameters can be found elsewhere. 17,18 The crystalline phase of the KNN films were analyzed using X-ray diffraction (XRD) with a Bruker D8 Advance instrument from Germany. The XRD analysis was performed using Cu−Kα radiation with a wavelength of 0.15418 nm.…”