Preparation of Nb-doped PZT Thin Film with High Piezoelectric Performance and Its Application to MEMS Devices

We have developed a method of forming PZT films on silicon substrates with a high piezoelectric coefficient using RF sputtering. Films have been formed on 6-inch wafers with thickness variation of less than +/− 5% across the entire wafer. Our PZT film has an unusually high content of Nb dopant (13%) which results in 1.7-fold higher piezoelectric coefficient than sputtered PZT films previously reported. The X-ray diffraction patterns of our PZT film formed on a 6-inch wafer demonstrate that the film is in a perovskite phase with (100) orientation which partly accounts for its high piezoelectric performance. One of the unique properties of our sputtered PZT film can be observed in the P-E hysteresis loop shifted to the positive electric field, suggesting that the polarization axes have been aligned in a certain direction beforehand, making a post-deposition polarization process unnecessary. We applied the PZT film to an ink-jet head and micro-mirror as a MEMS device application, and demonstrated high actuation performances of both devices. Original paper (Received December 20, 2013) * Advanced Marking Research Laboratories Research & Development Management Headquarters FUJIFILM Corporation 577 Ushijima, Kaisei-machi, Ashigarkami-gun, Kanagawa 258-8577 Japan ** FUJIFILM Dimatix, Inc. 2230 Martin Avenue, Santa Clara, CA 95050, U.S.A.