Sputtered high |d/sub 31/| coefficient PZT thin film for microactuators

High |d/sub 31/| coefficient PZT thin film for Si-based microactuators has been developed. Piezoelectric coefficient d/sub 31/ of around -100 pC/N was obtained and it is comparable to that of thick film or bulk PZT. The film was deposited on Pt/Ti/LTO/Si substrate by magnetron sputtering and annealed for obtaining perovskite structure. It was made clear that a <111> strongly oriented film has a higher |d/sub 31/| coefficient. Crystal orientation preference was controlled by ramp rate at post anneal process. Built-in stress and Young's modulus of PZT thin film have also been evaluated. It was shown that post anneal process significantly increases both mechanical characteristics. 10 minutes-annealed PZT thin film which has d/sub 31/ of -100 pC/N has a built-in stress of 380 MPa and a Young's modulus of 75 GPa.