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

Abstract

Metallorganic chemical vapor deposition (MOCVD) of thin (<100 nm) (PZT) films was performed for applications in high density (>16 megabit) 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 and 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 layer formation. © 2003 The Electrochemical Society. All rights reserved.