Gradient Study Of PZT Thin Films And Its Application In Microactuators

In recent years,with the development of MEMS technology,PZT（lead zirconate titanate）film is combined with MEMS technology,and PZT film has been widely used.In this paper,PZT films with good quality were prepared by sol-gel method,the effect of La doping modification on PZT films with different gradients was studied,the effect of different buffer layers on the properties of non-gradient PZT films was studied,and the corrosion of bottom electrode and PZT films was investigated.technology,and applied the gradient-free PZT film in the micro-actuator,characterized its vibration performance,applied it to the piezoelectric inkjet print head,and successfully ejected ink droplets.The research contents include the following aspects:（1）Prepare PZT precursors with different zirconium-titanium ratios,using different zirconium-titanium ratios in the precursors and the diffusion of Zr⁴⁺and Ti⁴⁺during heat treatment,using the gradient compensation method,using multiple spin coating-heat treatment methods to prepare PZT films with different gradients.The effect of La doping on different gradient films was investigated.The results showed that the SL film and the GF film showed a（100）preferred orientation,the GE film showed a random orientation,and La doping reduced the（100）orientation degree of each film;the GF-La film had a higher dielectric coefficient,reaching 1196.2,The remanent polarization was improved,2P_r reached26.21μC/cm²,the coercive field Ec was 44.4k V/cm,and the fatigue performance was also improved.Pb Zr O3,Pb Ti O3 and PZT with Zr/Ti=52:48 were introduced as buffer layers to guide the growth of non-gradient PZT films.The results showed that the dielectric constant of PZT/GF films was the largest,reaching a maximum value of 1049.7,an increase of 32.1%.The dielectric constant of the GF film reached 939.2,an increase of 18.2%,while the dielectric constant of the PZ/GF film was only 660.4,and the dielectric constant decreased by about 17.0%.（2）Explore the patterning process of the bottom electrode（Pt/Ti）and PZT thin films.The bottom electrode was patterned by wet etching,with BN308 as the masking layer,aqua regia as the Pt etching solution,and HF as the Ti etching solution.The results showed that the etching rate of Pt was about 2.22nm/s,and the etching rate of Ti was about 10nm/s.Prepare and study PZT corrosion solution,and study the relationship between corrosion rate and temperature.The results showed that the corrosion rate gradually decreases with time and increases with temperature.The average etching rate of a film with a thickness of 1μm was28.6 nm/s.The lateral side etching can be reduced by using multiple etching methods.（3）Piezoelectric micro-actuators based on different PZT films were fabricated and their vibration properties were characterized.The results showed that when the applied voltage was20 V,compared with the undoped PZT film,the maximum amplitude of the GF-La film reached 369.5 nm,an increase of 22.8%,and the maximum amplitude of the SL-La film reached 310.6 nm,an increase of 21.0%.An inkjet test system was built to test the jetting situation of the inkjet print head gradient-free PZT film.The results showed that the inkjet print head with GF-La film as the driving element can normally eject ink droplets,but some nozzle holes cannot be ejected normally due to the weak bonding of the chamber and the poor hydrophobic effect of the nozzle holes.