Pulsed Laser Deposition Of Lanthanum Strontium Cobalt Oxide Films Prepared By Electrical Performance Testing

The research topic of the integrated devices of ferroelectric thin films has gained much attention in recent years, which is an important branch of modern information science and technology. The core of the integrated ferroelectric devices is the heterostructure of perovskite ferroelectric and conducting thin film. In order to apply ferroelectric thin films in integrated devices, it is very important to prepare suitable electrode using suitable method, as the performance of electrode has determined the performance of ferroelectric thin films. The main topic of this thesis is to deposit the thin film of the conductive perovskite oxides using the pulsed laser deposition (PLD) technique and to study the influence of crystallization surface profile lattice mismatchonthe resistances of the films. The aim of the research is to apply the integrated ferroelectric devices and attain the structural matching of the interface of the electrode and the ferroelectric thin film and prolong lifetime of the integrated ferroelectric devices.La0.5Sr0.5CoO3 thin films have been prepared by pulsed laser deposition (PLD) on Si?SiO2/Si?Pt/Ti/ SiO2/Si and LaAlO3 substrates. The result of the measure of the degree of crystallization and surface profile of the films reveal that the degree of crystallization of film on LaAlO3 substrate is best; it on Pt/Ti/ SiO2/Si substrate is subsequent; and it on Si and SiO2/Si substrates with the condition of 600癈 and 50Pa is well. The films on Si?SiO2/Si and Pt/Ti/ SiO2/Si substrates have microcrazes in different degree. The degree of microcrazes of the films with in-situ is lightened, the surface profile of the film deposited in multiple layers with in-situ is improved signlly. But the films with ex-situ treatment have no apparent improvement.The resistance of La0.5Sr0.5CoO3 thin film has affinity with the degree of crystallization and surface profile of the films. The films on Pt/Ti/ SiO2/Si substrates have microcrazes too, but they have the least resistance, the reason perhaps is the electrons penetrate the La0.5Sr0.5CoO3 film and transmit on Pt film when the resistance of La0.5Sr0.5CoO3 thin film ismeasured, for the thickness of La0.5Sr0.5CoO3 thin film is light.In addition, the resistance anisotropy of La0.5Sr0.5CoO3 and La0.67Ca0.33MnO3 thin films on tilted LaAlO3 substrates have studied in this thesis. The result reveal that the La0.5Sr0.5CoO3 and La0.67Ca0.33MnO3 thin films grown on tilted substrates demonstrate resistance anisotropy, and the film on the substrate with the bigger tilting angle has the larger resistance anisotropy, it is agreeable to theoretical explanation. Otherwise, in the experiments we have discovered the laser induced thermoelectric voltage (LITV) of La0.5Sr0.5CoO3 thin films on tilted substrate and the gas sensitivity of La0.5Sr0.5CoO3 thin film, and their application foregrounds are quite extensive.