CHEMICAL-VAPOR-DEPOSITION OF (BA,SR)TIO3

SrTiO3 and (Ba, Sr)TiO3 thin films were fabricated on Si and Pt/TaOx/Si substrates by chemical vapor deposition (CVD) using Sr(DPM)(2), Ba(DPM)(2), Ti(O-i-C3H7)(4), and O-2 where DPM is dipivaloylmethanate or formally 2,2,6,6-tetramethyl-3,5-heptanedionate. The deposition system was operated in both thermal CVD mode and electron cyclotron resonance (ECR) plasma CVD Mode. Variations in individual Sr and Ti deposition rates with differing deposition conditions were investigated. The SrTiO3 and (Ba, Sr)TiO3 films were characterized with a view to discussing the step-coverage, crystal structure, and electrical properties. The step-coverage over the 300 nm wide SiO2 lines, with 500 nm height and 500 nm spacing, was 30 to 40%. The 40 to 100 nm SrTiO3 films, through the postdeposition annealing process, showed dielectric constants >140 with a leakage current density level <10(-7) A/cm(2) at 1 V. The prospects for applying the CVD (Ba, Sr)TiO3 films to giga-bit dynamic random access memory storage capacitors are discussed.