Study On Modification Of PZT Film For Piezoelectric Microactuators

In recent years,with the maturity of the PZT film preparation process,researchers are keen to find ways to improve the performance of thin films so that they can be widely uesd.In this paper,we chose the most common chemical preparation method to prepare PZT piezoelectric film by sol-gel method and characterized some properties of the film.The thickness of PZT film and spring structure were simulated and optimized by COMSOL software,which can provide parameter guidance for subsequent experiments.PZT films were modified by introducing PbZrO₃ seed layer and zwitterion of Dy and Er.The main content of the full text is as follows:(1)The parameters of PZT film thickness,spring structure width and the remaining PZT thickness in the spring structure were simulated by COMSOL software.The amplitude was larger when the thickness of PZT film was 1.4?m,the width of spring structure was 35?m,and the remaining PZT thickness in the spring structure was 0.6?m.(2)The effect of PbZrO₃ seed layer on the performance of PZT piezoelectric film was studied.The test results show that the PbZrO₃ seed layer with(111)preferred orientation can lead the PZT film to nucleate along(111)orientation and inhibit the growth of other orientations.The PbZrO₃ seed layer is also beneficial to the formation of a more compact columnar perovskite structure of PZT films.In terms of electrical properties,the dielectric and ferroelectric properties of PZT films decrease due to the anti-ferroelectric properties of PbZrO₃ material.However,under the action of guiding,compensating,blocking and forming low stress field by seed layer,the fatigue resistance of PZT film is enhanced.(3)The effects of Dy and Er doped ions on the properties of PZT films were studied and the doping modification mechanism was discussed.PDZT films with 0%-5%Dy concentration were prepared by Sol-Gel method.The test results show that the PDZT films doped with 0%to 2%Dy show the preferred orientation of(111),and the PDZT films doped with 3%to 5%Dy show the preferred orientation of(100).The perovskite structure of PZT films becomes denser with the introduction of low concentration of Dy ions.The residual polarization strength and relative dielectric constant of PDZT films doped with Dy2%reach the maximum value,and the ferroelectric and dielectric properties are obviously enhanced.In addition,the leakage current density of PDZT films doped with Dy 2%also decreased obviously.PEZT films with the same concentration were prepared by introducing erbium ion which is also a lanthanide element.The experimental results show that the introduction of Er ion changes the direction structure of the thin film,and the peak intensity of the PEZT film(100)is the highest when the doping concentration is less than 3%,and pyrochlorite phase appears when the doping concentration is greater than or equal to 3%.When the concentration of Er is 1%,the relative dielectric constant of PEZT film reaches the maximum,reaching1358.At the same time,the residual polarization strength of PZT films reaches the maximum of 11.28?C/cm².In addition,the fatigue resistance of PEZT films doped with Er 1%is also better than that of pure PZT films.(4)The piezoelectric microactuator with different Er doped PEZT thin films as driving elements were fabricated by conventional MEMS technology,and the vibration characteristics were characterized by Doppler vibration measurement system.Under the test condition of 10k Hz frequency and 20V voltage,the micro actuator with Er doped 1%PEZT film as driving element has the largest amplitude of 389.2 nm,which is 42.1%higher than that with pure PZT as the driving element.