MOCVD of PZT Thin Films with Different Precursor Solutions for Testing Mass-Production Compatibility

Abstract

Metallorganic chemical vapor deposition ͑MOCVD͒ of thin ͑Ͻ100 nm͒ Pb(Zr,Ti)O 3 ͑PZT͒ films was performed for applications in high density ͑Ͼ16 megabit͒ ferroelectric memory devices. The growth temperatures were set between 420 and 530°C to obtain a smooth surface morphology and to prevent damage to the underlying reaction barrier layer. A dome-type CVD chamber with a single-or double-cocktail precursor solution liquid delivery system was used for deposition. Four different precursor solution sets were investigated from the viewpoint of mass-production compatibility. The types of solvents had a great influence on the vaporizer lifetime and the level of oxygen incorporation into the PZT film that critically affected the electrical performance. The deposition behavior, including the within-wafer-thickness uniformity, was also dependent on the type of the precursor solutions. The oxygen injection method had a great influence on the Pb composition, the interfacial reaction between the film and the Ir electrode as well as the electrical properties. When nonpreheated oxygen was injected, the interfacial reaction became a serious problem resulting in the formation of IrO 2Ϫx and Pb x Ir y O z layers without sufficient oxygen incorporation into the PZT film. Preheated oxygen was effective in incorporating Pb into the PZT films without serious interfacial reactions except for thin IrO 2Ϫx layer formation.

Metalorganic chemical vapor deposition of atomically flat SrRuO3 films on stepped SrTiO3 substrates

“…The resistivity of these films was 240-280 ⍀ cm irrespective of R͓Ru͑C 7 H 11 ͒ ͑C 7 H 9 ͔͒. 9,13 The resistivity value is lower than the previously reported data for SrRuO 3 single crystals, but is almost the same as the reported data for MOCVD-SrRuO 3 films from the Sr͑C 11 13 The data shown in Fig. 1 clearly show that the stoichiometric SrRuO 3 films with low resistibility were obtained for a wide range of the supply ratio of the source.…”

“…In the present study, R͓Ru͑C 7 H 11 ͒͑C 7 H 9 ͔͒ was changed by ᐉ and P͑vessel͒ under constant R͓Sr͑C 11 …”

“…[8][9][10] However, growth of SrRuO 3 layers by metal organic chemical vapor deposition ͑MOCVD͒ has not been reported in spite of the fact that MOCVD can provide highquality films with a largely uniform film thickness, composition, and electrical properties, suitable characteristics for mass production. 11 The growth of epitaxial SrRuO 3 films by MOCVD at 750°C has previously been reported. 12,13 For MOCVD-SrRuO 3 film deposition, a large process window in composition against the supply ratio of Sr and Ru sources has previously been observed and high-quality films with various orientations were successfully grown.…”

Preparation of Pb(ZrxTi1 - x)O3 Films on Trench Structure for High-Density Ferroelectric Random Access Memory

“…The compositional non-uniformity is observed only on the Pb elements, even though two different sets of precursors used the same molecular structure of Pb(tmhd) 2 . Efficient oxidation of Pb is quite a difficult compared to other elements of Zr and Ti, which make it difficult to incorporate Pb into the film [6]. It is reasonable to assume that the oxidation of Pb occurs after most of the Zr and Ti elements oxidize.…”

Fabrication of Pb(Zr,Ti)O3 Thin Films by Liquid Delivery MOCVD Using a Cocktail Source with Pb(DPM)2, Zr(MMP)4 and Ti(MMP)4

“…TilMMPlj and the mixture of them were utidergone under an Ar atmosphere at the heating rate of 10 C/min, The TG curves of them are sbown in Fig. 2 , also, reported tbat theMETHD-basedcocktail source required the higher vaporizer temperature [17]. Tbe DTA measurements of PMDPM)., Zr{MMP)4 and Ti(MMP)4 were undergone sepiu^ately under an O2 atmospbere at tbe heating rate of 10°C/min.…”