Effects of substrate temperature and ambient oxygen pressure on growth of Ba(Fe_(1/2)Nb_(1/2))O_3 thin films by pulsed laser deposition

摘要

Ba(Fe1/2Nb1/2)O3 thin films were grown on Pt/TiO2/SiO2/Si substrates with pulsed laser deposition (PLD) at temperatures ranging from 823 to 923 K with the varied ambient oxygen pressure. X-ray diffraction (XRD) data confirmed the single phase of polycrystalline Ba(Fe1/2Nb1/2)O3 thin films. The effects of substrate temperature and ambient oxygen pressure on the surface morphologies of the thin films were investigated by atomic force microscopy (AFM) and the growth dynamics of thin films was discussed. Larger grains and denser surface morphologies were observed with increasing substrate temperature. While finer grains were produced with increasing ambient oxygen pressure due to more frequent collisions between the ejected species and ambient oxygen molecules. The influence of the substrate temperature and ambient oxygen pressure on the dielectric properties was also discussed. Improved dielectric constant and decreased dielectric loss was observed for the thin film deposited at evaluated temperature.