Recent development in the preparation of ferroelectric thin films by MOCVD

Recent research by our group, concerned with the preparation of ferroelectric thin films by MOCVD, is summarized. MOCVD has been investigated as a most practical preparation method to realize a high-density FeRAM, because of the good step coverage and the uniform composition and film thickness over a large area. In addition, it has recently become possible to decrease the process temperature to obtain films retaining a large remanent polarization by MOCVD. In fact, Pb(Zr,Ti)O-3 (PZT) and SrBi2Ta2O9 (SBT) films having good ferroelectricity were obtained at 415 and 570 degreesC, respectively. Moreover, new materials to overcome the problem of the present materials, such as PZT, SBT, and (Bi,La)(4)Ti3O12 (BLT), were discovered by using MOCVD because the composition of the film was easily changed by the input source gas composition.