Preparation and characterization of SrTiO₃ thin films using ECR plasma assisted MOCVD

SrTiO₃ thin films were prepared on Si(p-type 100) and Pt/SiO₂/Si substrates using ECR plasma (or without ECR plasma) assisted MOCVD. Sr(TMHD)₂ and Ti-isopropoxide were used as Sr and Ti metal organic sources, respectively. Perovskite SrTiO₃ films were obtained at relatively low temperature of 500°C using ECR oxygen plasma. Experimental results indicated that higher deposition temperature and ECR oxygen plasma increase the crystallinity, the dielectric constant and the leakage current density. The dielectric constant and the dielectric loss were 222 and 0.04, respectively, for 1234 angstrom thin SrTiO₃ film (Sr/(Sr+Ti)=0.5). The leakage current density was 3.78 × 10^-7 A/cm² at 1.0V, and the dielectric breakdown field was 0.57MV/cm. SEM analyses showed that SrTiO₃ films have a uniform and fine grain structure. In terms of step coverage, a lateral step coverage of 50% at 0.8μm step (the aspect ratio was 1) was obtained with the thickness uniformity of ±0.5% and the composition uniformity of ±1.2% at 4″ wafer.