CHEMICAL SOLUTION DEPOSITION AND ELECTRICAL PROPERTIES OF (100)-PREDOMINANT BaTiO₃ THICKER FILMS

ABSTRACT

Lead-free piezoelectric films with thickness larger than 1 μm integrated on silicon substrate have been receiving considerable attention for environmental concern and potential applications in micro-electro-mechanical systems. By chemical solution deposition, it is possible to process (100)-predominant 1 μm BaTiO₃ films on LaNiO₃/Pt/TiO _x /SiO₂/Si substrates by using the same thinner high crystallinity columnar films as buffer layers. We point out that this kind of buffer layer on the surface of LaNiO₃/Pt electrode is effective to enhance the crystallinity and orientation degree of the BaTiO₃ films. The 1 μm BaTiO₃ films showed good dielectric and insulative characteristic against applied field. Also, the (100)-predominant 1 μm BaTiO₃ films have excellent piezoelectric properties, piezoelectric coefficients d ₃₃ higher than 50 pm/V have been detected by the atomic force microscope on the bare films, which is comparable to that of Pb(Zr,Ti)O₃ films. These results indicate that the highly (100)-oriented BaTiO₃should be a promising candidate as the lead-free piezoelectric films for micro-electro-mechanical systems applications.

Keywords:

• (100)-oriented BaTiO₃ thick films
• chemical solution deposition
• LaNiO₃ seeding layer
• BaTiO₃ buffer layer
• dielectric properties
• piezoelectric properties