Step Coverage and Electrical Properties of (Ba, Sr)TiO3Films Prepared by Liquid Source Chemical Vapor Deposition Using TiO(DPM)2

Thin films of (Ba, Sr)TiO3(BST) with high dielectric constant were prepared on Pt/ SiO2/Si substrates of 6-inch-diameter by liquid source chemical vapor deposition using Ba(DPM)2, Sr(DPM)2and TiO(DPM)2(DPM=dipivaloylmethanato; C11H19O2) dissolved in tetrahydrofuran (THF). The reproducibility of ±3 % for the film composition was achieved by optimizing the deposition procedures. It was found that the coverage of 72%, obtained at the substrate temperature Ts=753 K, was better than those obtained using other Ti sources such as Ti(O-i-Pr)4(TTIP) and Ti(O-i-Pr)2(DPM)2. The electrical properties of the 480-Å-thick BST film, deposited at Ts=753 K using TiO(DPM)2, were as follows: dielectric constant ?=230, equivalent SiO2thickness teq=7.8 Å, leakage current density JL=6.7×10-6A/cm2at 1.65 V and dielectric loss tan ?=0.013.