Characterization of epitaxial Pb(Zr,Ti)O₃thin films deposited by pulsed laser deposition on silicon cantilevers

Abstract

This paper reports on the piezoelectric-microelectromechanical system micro-fabrication process and the behavior of piezoelectric stacks actuated silicon cantilevers. All oxide layers in the piezoelectric stacks, such as buffer-layer/bottom-electrode/film/top-electrode: YSZ/SrRuO 3 /Pb(Zr,Ti) 3 /SrRuO 3 , were grown epitaxially on the Si template of silicon-on-insulator substrates by pulsed laser deposition. By using an analytical model and finite element simulation, the initial bending of the cantilevers was calculated. These theoretical analyses are in good agreement with the experimental results which were determined using a white light interferometer. The dependences of the cantilever displacement, resonance frequency and quality factor on the cantilever geometry have been investigated using a laser-Doppler vibrometer. The tip displacement ranged from 0.03 to 0.42 μm V −1 , whereas the resonance frequency and quality factor values changed from 1010 to 18.6 kHz and 614 to 174, respectively, for the cantilevers with lengths in the range of 100-800 μm. Furthermore, the effect of the conductive oxide electrodes on the stability of the piezoelectric displacement of the cantilevers has been studied.

Micro Coriolis MASS flow sensor driven by integrated PZT thin film actuators

“…Figure 7 shows the measured current (blue curve). By integrating the current the polarization hysteresis loop can be calculated [6] which is also shown in the figure (red curve). It can be concluded that the coercive field Ec is around 21kV/cm.…”

“…The PLD deposition process has been described in [6]. After deposition of these layers we have the cross section shown in Figure 5(d).…”

Enhanced electrical and magnetic properties in La0.7Sr0.3MnO3thin films deposited on CaTiO3-buffered silicon substrates

“…The integration of these epitaxial functional oxides with silicon substrates offers significant opportunities for applications. [1][2][3][4][5][6][7][8] Among them are micro-electromechanical systems (MEMS) based on epitaxial piezoelectric layers [9][10][11][12][13] and suspended bolometers based on epitaxial La 0.7 Sr 0.3 MnO 3 thin films. 14 The use of silicon substrates greatly facilitates the fabrication of MEMS and suspended bolometers, where three-dimensional structures can be efficiently realized by volume silicon micromachining using conventional techniques such as isotropic etching in alkaline solutions (KOH, TMAH, etc.)…”

Epitaxial perovskite oxide devices fabricated by lift-off technology

“…Conventional epitaxial piezo-MEMS devices fabricated using silicon on insulator (SOI) as substrate material contains relatively thicker (typically 3-50 μm) top Si layer from the substrate on the bottom side of the device [59]. This residual Si layer makes the MEMS devices heavier, often reducing their functional performances, for example the limit of detection (LOD) when used as mass sensors [60].…”

“…These substrates are comprised of two Si crystal (with varying thickness, often the thicker one at bottom) sandwiching an intermediate SiO 2 layer, termed as buried oxide layer (BOX). Figure 5.1 shows a typical fabrication scheme for fabrication of epitaxial PZT MEMS devices on SOI substrates [59]. The fabrication strategy requires back-side etching of the bottom Si layer prior to high temperature deposition of the oxide stack, mostly utilizing dry reactive ion etching.…”