Growth Behavior and Electrical Properties of a (Na_0.5K_0.5)NbO₃Thin Film Deposited on a Pt/Ti/SiO₂/Si Substrate Using RFMagnetron Sputtering

Abstract

A crystalline (Na0.5K0.5)NbO3 (NKN) phase was formed for a film grown at 600°C, but a K5.75Nb10.85O30 (KN) second phase was also observed in this film. Formation of the KN phase was due to the evaporation of Na2O. A homogeneous NKN phase was developed in the film grown at 300°C and annealed at 800°C under a Na2O atmosphere. This film exhibited the following good electric and dielectric properties: a high dielectric constant of 237.4 with a dissipation factor of 0.93% at 100 kHz, a low leakage current density of 1.0 × 10−8 A/cm2 at 0.1 MV/cm2, and the high Pr and d33 values of 21.1 μC/cm2 and 64.5 pm/V, respectively.

Synthesis of [10Ῑ]‐Oriented (Na1−xKx)NbO3 Platelets by Using Hydrothermally Produced (K8−8xNa8x)Nb6O19·nH2O Precursor

“…Therefore, it is assumed that larger amounts of Na 2 O evaporated during annealing than K 2 O. Similar results were also observed for NKN films . Moreover, the composition of the KNNH platelets was close to (Na 4 K 4 )Nb 6 O 19 ·9H 2 O, although they were produced from a precursor containing a high concentration of NaOH (or KOH).…”

“…In order to investigate the formation process of (Na 1Àx K x ) NbO 3 platelets, XRD patterns were obtained from KNNH According to the previous work on NKN thin films, Na 2 O and K 2 O evaporated when the growth temperature exceeded 300°C. 29,30 Therefore, it is assumed that significant amounts of Na 2 O and K 2 O evaporated from the KNNH specimen when the annealing temperature exceeded 400°C, resulting in the transformation of the KNNH platelets into the (Na 1Àx K x )NbO 3 platelets.…”

Magnetodielectric effect in lead-free multiferroic CoFe2O4/K0.5Na0.5NbO3 bilayers

“…The KNN films are polycrystalline without preferential orientation. K-Nb-O second phase is observed in these films due to the sublimation of Na at high growth temperature [17]. A post annealing treatment at 800 1C in air only slightly improves the crystallinity of KNN film, as shown in Fig.…”

Electrical Properties of a 0.95(Na0.5K0.5)NbO3–0.05CaTiO3 Thin Film Grown on a Pt/Ti/SiO2/Si Substrate

“…NKN‐CT films were grown on a Pt–Si substrate by RF magnetron sputtering using a stoichiometric NKN‐CT ceramic target with a diameter of 3‐inch, which was synthesized using the conventional solid‐state method. According to a previous study, Na 2 O or K 2 O evaporation occurs for NKN films grown above 300°C . Therefore, the deposition of NKN‐CT films was carried out at 300°C under an argon and oxygen (Ar:O 2 = 4:1) mixed atmosphere, where the total pressure was 10 mTorr and sputtering power was 80 W. A postannealing process was performed at 750°C–880°C for 2 h under the Na 2 O and K 2 O atmospheres.…”