Domain structure and electrical properties of highly textured PbZrxTi1−xO3 thin films grown on LaNiO3-electrode-buffered Si by metalorganic chemical vapor deposition

Abstract

Thin films of highly (100) textured fine-grain (lateral grain size ≅0.1 to 0.15 μm) PbZrxTi1−xO3 (PZT) (x = 0 to 0.7) were grown on conductive perovskite LaNiO3-buffered platinized Si substrates by metalorganic chemical vapor deposition. Domain configuration and crystalline orientation were studied using x-ray diffraction and transmission electron microscopy. The predominant domain boundaries of Ti-rich tetragonal-phase PZT and Zr-rich rhombohedral-phase PZT were found to be on the (110) planes and (100) planes, respectively. The equilibrium domain widths were observed and estimated numerically on the basis of transformation strain, grain size, and domain boundary energy. The peak value of the dielectric constant was 790 near the morphotropic boundary. Hysteresis behavior of these PZT thin films was demonstrated. A decrease in coercive field with the increment of Zr content was found; this variation was attributed to domain density and the multiplicity of polarization axes. Furthermore, the low leakage current (J ≤ 5 × 10−7 A/cm2 at V = 4 V) was observed for all samples, and the involvement of several possible conduction mechanisms was suggested.