Preparation And Dielectric Properties Of CaCu₃Ti₄O₁₂ Thin Films Using Radio Frequency Magnetron Sputtering

Dielectric materials in semiconductor devices have two of the most important applications:one as the gate dielectric layer of field-effect transistor device; another as dynamic random access memory (DRAM) capacitor dielectric materials。CaCu₃Ti₄O₁₂ (CCTO) material since its dielectric properties were found has been widespread concerned because it has high dielectric constants and is not sensitive to temperature changes。Both ceramics and the thin-film materials have high dielectric constant, and with the temperature changed in the large range the dielectric constant has remained steady .The current research work focused on why CCTO has the gigantic dielectric constant ,the " intrinsic " or " nonintrinsic " origin。In this work an attempt was made to prepare CCTO thin films by using radio frequency(RF) magnetron sputtering on Pt/Ti/SiO₂/Si substrates。As-deposited CCTO films were treated by annealing at various temperatures。X-ray diffraction, dielectric spectroscopy were used to study the influence of different annealing temperatures and different electrode materials on the structure and dielectric properties of CCTO thin films。X-ray diffraction patterns demonstrated that the annealed CCTO polycrystalline films has been (220) preferred orientation。And we discover that the crystalline CCTO films exhibit better dielectric properties than the amorphous films.Through the different electrodes materials and electrode preparation processes the dielectric properties of the CCTO films suggests the possibility that the charge carriers accumulate at the interface between the film surface and electrode, resulting in interfacial space-charge polarization which has great contribution to the colossal dielectric constants。...