Deposition control of La in the preparation of (Bi,La)4Ti3O12 films by liquid-delivery MOCVD

We attempted to prepare lanthanum substituted bismuth titanate ((Bi,La)(4)Ti3O12:BLT) thin films by a liquid-delivery MOCVD method. However, La was not sufficiently deposited in the film when beta-diketonates were used as La precursors. We have already reported that the Nd deposition amount in the film increased by using the adduct, 1,10-phenanthroline (phen), to Nd precursor of beta-diketonate,Nd(TMOD)(3). Expecting a similar effect, La precursors with the adduct were used in order to prepare BLT films. It was then discovered that phen could increase the deposition amount of La as an adduct to La(TMOD)3. By using the precursor solution including Bi(p-Tol)(3), La(TMOD)(3)phen and Ti(Oi-Pr)(2)(DPM)(2) with a molar ratio of 3.25:0.75:3 as an improved source, a preferentially c-axis oriented BLT film was obtained on Pt/Ti/SiO2/Si at the substrate temperature of 600 degrees C. One of the causes of the insufficient deposition of La by using La(TMOD)3 in BLT preparation was presumed that Bi(p-Tol)(3) attached to La(TMOD)(3) in a solution.