Flexible Heterogeneous Integration Fabrication And Study On Electrical Performance Of PZT Piezoelectric Thin Film

As a functional ferroelectric material,PbZr₎0.53)Ti_0.47O₃?PZT?ceramic has been widely used in the fields of micro-mechanical systems,energy collection,intelligent sensing,ferroelectric storage and so on.However,with the increasing popularity of intelligent terminal devices,traditional piezoelectric ceramic devices can not meet the development needs of miniaturization,flexibility and portability of wearable devices.Therefore,how to fabricate flexible PZT thin film by a simple,efficient and low-cost method is a key problem to be solved urgently in the application of flexible wearable devices.In this paper,the controlled spalling technology?CST?is innovatively used to realize the spalling of PZT films on rigid substrates,and finally prepare flexible PZT piezoelectric film.Firstly,PZT film is prepared on the Si substrate and sapphire by Sol-Gel technology.The films have a good crystallization and uniform grain distribution.Besides,they have no cracks on the surface.Second,the fracture path and mechanism of thin film/brittle base system in controlled spalling process are theoretically analyzed and studied.Two systems of thin film/Si and thin film/sapphire are established,respectively.The effects of different hardness substrates on spalling process are studied.In the thin film/Si system,it was found that the thicker the lanthanum nickelate?LNO?within a certain thickness range,the better the film formation and crystallization of PZT film.The controlled spalling of PZT film is realized by controlling the thickness of LNO layer.In the thin film/sapphire system,the controlled spalling of PZT film is accomplished by changing the current density of the plating bath.Finally,it is concluded that the film/sapphire system is relatively simple to operate and does not involve wet etching process,which can greatly save the cost of experimental materials.The structure and morphology of the spalled PZT film are characterized by XRD,Raman spectra,SEM and EDS.The results show that the spalled PZT film still remains the polycrystalline perovskite structure and has a dense surface without any cracks.The influence of curving degree on P-E curve and leakage current of flexible PZT film is analyzed.It is found that the values of residual polarization,saturation polarization and leakage current of PZT film did not change significantly when the PZT film is bended.The results show that PZT film has a good mechanical and ferroelectric property under different bending deformation.In addition,the phase-voltage and amplitude-voltage curves of PZT piezoelectric thin film grown on flexible substrates are studied.It is found that PZT thin film grown on flexible substrates has a better piezoelectric response than that on rigid substrates.Therefore,the flexible PZT thin film has a good application prospect on wearable ferroelectric microelectronics.