The properties of tantalum modified lithium niobate thin films prepared by a diol-based sol-gel process

Abstract

LiNbTa x O 3 thin films were successfully deposited on Pt(111)/Ti/SiO 2 /Si(100) substrates by spin coating with a diol-based sol-gel technology and rapid thermal annealing. The effects of various processing parameters, including Ta content (0) and heating temperature (500 ~ 800 °C), on the growth and properties of thin films were investigated. With the increase of Ta content, the grain size of film decreased slightly, and the maximum f factor (the degree of c -axis orientation) of the films were obtained in the composition of x = 0.2. As the composition of film varied from x = 0 to x = 1, the relative dielectric constant of film increased from 33 up to 62, and the dielectric loss factor (tan δ ) also increased from 0.00374 to 0.00686, respectively. The coercive field, Ec , and remanent polarization, Pr , decreased but pyroelectric coefficient, γ , increased from 2.76 × 10 −8 up to 4.51 × 10 −8 C/cm 2 K. The pyroelectric figures of merit, Fv and Fm , indicated that film with Ta content of 20 mol% and heating temperature of 700 °C exhibited the optimized pyroelectric characteristics and could be applied for high-performance pyroelectric thin-film detectors.