Deflection of wafers and cantilevers with Pt/LNO/PZT/LNO/Pt/Ti/SiO2 multilayered structure

The present paper describes a Pt/LNO/PZT/LNO/Pt/Ti/SiO2 multilayers deposited on 4-inch Si wafers. We have evaluated the variation of the deflection of the Si wafers with deposition of each of the thin films. The deposition of the multilayers has resulted in downward deflection (center is higher than edge) of the Si wafers. The multilayers have been also deposited onto SOI wafers and fabricated into piezoelectric micro cantilevers through MEMS bulk micromachining. The micro cantilevers have shown the upward deflection. We have characterized the ferroelectric and piezoelectric properties of the PZT thin films through electrical tests of the micro cantilevers. The dielectric constant, saturation polarization, remanent polarization and coercive field were measured to be 1050, 31.3 mu C/cm(2), 9.1 mu C/cm(2) and 21 kV/cm, respectively. The transverse piezoelectric constant, d(31), was measured to be -110 pm/V from the DC response of the micro cantilevers. (C) 2007 Elsevier B.V. All rights reserved.