Optimization of PbTiO₃ seed layers and Pt metallization for PZT-based piezoMEMS actuators

Abstract

This work attempts to optimize past research results on lead zirconate titanate (PZT) using the fabrication processes at the U.S. Army Research Laboratory so as to achieve a high degree of {001} texture and improved piezoelectric properties. A comparative study was performed between Ti/Pt and TiO 2 /Pt bottom electrodes. The results indicate that the use of a highly oriented {100} rutile phase TiO 2 led to highly textured {111} Pt which in turn improved both the PTO and PZT orientations. PZT (52/48) and (45/55) thin films with and without PTO seed layers were deposited and examined via x-ray diffraction (XRD) methods as a function of annealing temperature. The seed layer provides significant improvement in the {100} orientation generally, and in the {001} subset of planes specifically, while suppressing the {111} orientation of the PZT. Improvements in the Lotgering factor (f) were observed from an existing Ti/Pt/PZT process (f 5 0.66) to samples using the PTO seed layer deposited onto the improved Pt electrodes, TiO 2 /Pt/PTO/PZT (f 5 0.96).

Texture control in lead zirconate titanate multilayer thin films

“…This corresponds to the summation of the individual capacitance, 44.1 nF, of each of the 4 layers summarized in the insert of Fig. 5(b) at 0 V. In the parallel configuration, the capacitor exhibited a tuning ratio of 3.4 from 0 V to 8 V as compared with a tuning ratio of 2.1 for a single-layer 0.5-µm pZT capacitor fabricated in previous work [22] following a similar process. a second set of samples was prepared to evaluate the piezoelectric induced deformation in cantilevers.…”

“…4(a)]. By the top-most pZT layer deposition, orientation across the entire stack resembles a randomly oriented pZT without any film optimization on Ti/pt electrodes instead of highly (111)-optimized Tio 2 /pt electrodes [22]. sample B [ Fig.…”

Millimeter-Scale Traveling Wave Rotary Ultrasonic Motors

“…To demonstrate the rotary motion, stators were fabricated using the process flow described in [2]. Details of the PZT deposition process can be found in [20]. Once the stator components are released, the device die are attached to a package using double-sided Kapton tape.…”

Influence of seed nano-crystals on electrical properties and phase transition behaviors of Ba0.85Sr0.15Ti0.90Zr0.10O3 ceramics prepared by seed-induced method

“…[19,20] Many researchers have carried out developing electrical properties of films by inserting a seed layer into a film preparation procedure for controlling the grain orientation and crystal orientation direction as well as improving the ferroelectric and piezoelectric properties of films. [21,22] The addition of seed nano-crystals may play on important role in the powder preparation such as to increase the reactivity of precursor, the stabilization of perovskite phase, and the homogeneity of the solid solution. The perovskite phase can be formed at a lower calcination temperature; moreover, using the seed could improve the electrical properties of piezoelectric ceramics.…”