The fabrication of Pb(Zr,Ti)O3 films on a Al/Al2O3 structure employing a crack amendment process

Pb(Zr,Ti)O₃ (PZT) thin films with lower gel concentration of 0.2 M to 0.3 M were deposited on Al/Al₂O₃ substrate via a sol-gel process, using lead acetate, zirconium n-propoxide and titanium isopropoxide as raw precursors, propyl alcohol as a solvent and acetate acid as a chelating agent and catalyst. After a batch of step (drying, pre-baking), sintered at higher temperature the amorphous PZT thin films were changed to perovskite-type crystal structure. The effect of variables such as gel solutions concentration and heating rate on morphology were investigated to conduct for preparing crack-free PZT thin films. The results showed that the cracking problem is reduced by employing for lower gel concentration 0.2 M with drying at 150°C for 5 min and pre-baking at 350°C for 10 min and then sintering at 700°C for 30 min with heating rate 50°C/min. We also measured P-E hysteresis loop using Sawyer-Tower circuit, the values of the remanent polarization (P_r) and coercive field (E_c) are around 11.39 c/cm² and 84.52 KV/cm, respectively. We also reported on the preparation and performance of a SAW resonator on PZT piezoelectric thin films coated on Al/Al₂O₃ substrate. Because of existing porous nature, crack-free PZT thin films were further surveyed for satisfactory SAW and FBAR devices on broadband application based on Al/Al₂O₃ structure.