New Multilayer Architectures for Piezoelectric BaTiO_3 Cantilever Systems

摘要

The fabrication and characterization of released cantilevers in new multilayer thin films architectures is reported. In contrast to previous works, the cantilevers are produced without etching of the substrate and are based on lead free piezoelectric materials. The three architectures are: SrRuO_3/BaTiO_3/MgO/SrTiO_3/YBa_2Cu_3O_7, SrRuO_3/BaTiO_3/SrRuO_3/YBa_2Cu_3O_7 and SrRuO_3/BaTiO_3/MgO/SrTiO_3/YBa_2Cu_3O_7, SrRuO_3/BaTiO_3/SrRuO_3/YBa_2Cu_3O_7. It is shown that the different architectures allow a choice of the orientation of the polar axis in piezoelectric layers, in plane (d_(33) mode) or out of plane (d_(31) mode). Both configurations may be utilized in piezoelectric energy harvesting devices. Released cantilevers with the above layer sequences have been produced with lengths ranging from, 100 μm to 250 μm. The residual stress after the release of the cantilevers produces an upward bending, the distance between the cantilever tips and the substrate varies between 20 μm and 45 μm. This distance would allow the sufficient vibration amplitude to enable the cantilevers to be used as micro-generators. Measurements of Young Modulus of the cantilevers and of polarization hysteresis loop are reported.