Synthesis of thin films of polycrystalline ferroelectric BiNbO4 on Si by pulsed laser ablation

The stibiotantalite (ABO(4)) family includes a number of ferroelectrics and antiferroelectrics with excellent potential for applications. We report the deposition of phase-pure, polycrystalline thin films of BiNbO4 on Si(100) substrates using pulsed laser ablation. The deposition conditions were optimized with respect to substrate temperature, laser parameters, and the ambient oxygen pressure. The films were characterized by x-ray diffraction, energy dispersive x-ray analysis, and Raman spectroscopy, while their microstructure was studied by atomic force microscopy and scanning electron microscopy. Dielectric hysteresis studies indicated that films with a thickness below approximate to 250 nm are ferroelectric, while thicker ones are antiferroelectric.