Growth of bismuth oxide films by direct liquid injection-metal organic chemical vapor deposition with Bi(tmhd)(3) (tmhd : 2,2,6,6-tetramethyl-3,5-heptanedione)

Abstract

Bismuth oxide films were deposited at 225-425 degreesC by direct liquid injection (DLI)-metal organic chemical vapor deposition (MOCVD) process with Bi(tmhd)(3) (tmhd : 2,2,6,6-tetramethyl-3,5-heptanedione) dissolved in n-butylacetate. The deposition rate of Bi2O3 film was determined by surface reaction with the apparent activation energy of 15 kcal/mol. The growth rate was decrease above 325 degreesC because of the gas phase dissociation of the precursor. The Bi2O3 film deposited at 300 degreesC was amorphous, while the film annealed at temperatures above 550 degreesC showed monoclinic a-phase. The grain size and surface roughness of the annealed film were increased with the increase of the annealing temperature up to 650 degreesC. At 750 degreesC, the monoclinic alpha-Bi2O3 film was changed into the cubic bismuth silicate due to the reaction with Si substrate. The dielectric constant of Bi2O3 films deposited at 300 degreesC was about 32 and the film showed a leakage current of 3.15 x 10(-7) A/cm(2) at 3 V (0.33 MV/cm). The thickness of Bi oxide Bi silicate films used in the C-V and I-V measurement was 92 and 140 nm, respectively. (C) 2004 Elsevier B.V. All rights reserved.