BaZn 1/3Ta 2/3O 3 (BZT) ceramics are widely used in current microwave communication applications due to the material's large-dielectric constant (ε r > 25), ultra-low loss tangent (tan δ < 2×10 -5 at 2 GHz) and a near-zero temperature-coefficient of resonant frequency (τ f∼O). In this paper, we report the first growth of epitaxial BZT thin films. The films are grown on MgO substrates using pulsed laser deposition. X-ray diffraction data indicate the films have a disordered pseudocubic perovskite structure with a small tetragonal distortion (i.e. a = b = 4.100 A; c = 4.088 A). An optimized substrate temperature of 575°C results in films which are over 98% oriented in the (001) direction and are relatively smooth (rms roughness of 5.2 A). X-ray diffraction φ scans of off-axis (202) reflection show four-fold symmetry, indicating a high degree of in-plane epitaxy, albeit with small angle grain boundaries. The refractive index of epitaxial BZT films is inferred to be 5 from Fabry-Perot fringes in optical transmission spectra. Substrate temperatures during growth are limited to ∼600°C as a result of Zn loss.
|Original language||English (US)|
|Title of host publication||Materials Research Society Symposium - Proceedings|
|Number of pages||5|
|Publication status||Published - 1999|
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials