Multi-target reactive sputtering—A promising technology for large-area Pb(Zr,Ti)O3 thin film deposition

Beyond target diameters of 100 mm, multi-target reactive sputtering becomes a promising technology for ferroelectric thin film deposition. The main advantages of multi-target sputtering technology are: (i) thin films with precise composition control, (ii) stoichiometric variations on the target surface during repeated use are prevented by target preconditioning and operation in the metallic mode, and (iii) higher deposition rate due to sputtering from metals in the metallic mode. The latter requires a much greater precision in control of the partial pressure of oxygen, e.g., by a plasma emission monitor. In this work, Pb(Zr,Ti)O3 thin film deposition on 150 mm silicon wafers by an industrial system is demonstrated. This technology can be easily scaled-up for larger silicon wafers and is compatible with standard semiconductor technology. Films deposited onto ZrO2 buffer layers were polarized in-plane and they are suitable for piezoelectric MEMS application.