Japanese Journal of Applied Physics · 2010 · 24 citations · 12 references
Natural SciencesMaterials EngineeringMaterials ScienceCeramic MaterialsCeramicsThin FilmsFerroelectric CeramicsFerroelectric MaterialsPerovskite MaterialsPiezoelectric CeramicsPiezoelectric MaterialsThin-film MaterialsLattice StrainLattice Strain EngineeringLead-free Piezoelectric CeramicsLead-free PiezoelectricsPerovskite Crystal StructurePiezoelectric PropertiesStrain Effects On Ferroelectric PropertiesThin Film Ferroelectrics
(K,Na)NbO 3 (KNN) films with very high transverse piezoelectric coefficient d 31 , which attained values comparable to those of Pb(Zr,Ti)O 3 (PZT) films for the first time, were successfully deposited on Pt/Ti/SiO 2 /Si φ 4-in. substrates by RF magnetron sputtering. These films were polycrystalline and had pseudo-cubic perovskite structure with a <001> preferred orientation. Furthermore, we focused on the effect of lattice strain on d 31 of KNN to clarify the relationship between the piezoelectric properties and structural parameters apart from orientation. We found that - d 31 increases with decreasing lattice strain c / a ratio of KNN when the in-plane lattice parameter a increases and the out-of-plane lattice parameter c decreases. By controlling the lattice strain c / a ratio strictly and maintaining a homogeneous strain, we achieved a high d 31 (∼-100 pm/V) that can be uniformized on φ 4-in. substrates and with a standard deviation that decreases to about 4 pm/V.
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