Preparation And Dielectric Properties Of CaCu₃Ti₄O₁₂ Ceramics And Pulsed Laser Deposition Of CaCu₃Ti₄O₁₂ Thin Films

In this work, the polycrystalline samples of CCTO compounds were prepared by a high temperature solid-state reaction technique. It's found that sintering temperature and holding time can improve the density, grain size and dielectric properties of the material. The dielectric constant and loss tangent of sample sintered at 1100℃can reach 6030 and 0.317 at 1MHz. If the holding time is 72h, the dielectric constant and loss tangent will be 11880 and 0.250.The material's loss tangent can be reduced by altering the CuO content and doping MgO or SiC. The loss tangent of samples with Cu3.2 or SiC 5.0wt% can be reduced to 0.2974 or 0.2351 due to the impurity at the frequency of 1MHz. When the doping content of MgO is 5.0mol%, the reduction of loss tangent is from 0.3463 to 0.2869 at 1MHz, and this method can't change the phase.And it is very important to deposit CCTO thin film on Si substrate, which is more compatible with very large-scale integrated circuits than oxide substrates.In this thesis, we study the deposition conditions of the CCTO thin films on Si (100) substrate by pulsed-laser deposition (PLD). With the help of X-ray Diffraction (XRD) and Scanning Electron Microscope (SEM), it can be found that the main orientation, density, grain size and roughness are influenced by the substrate temperature, oxygen pressure and laser output energy. CCTO thin films with pure perovskite structure and high density can be obtained at the substrate temperature above 750℃, oxygen pressure above 15Pa and laser output energy above 100mJ/pulse.