Microstructural analysis of integrated pin-shaped two-dimensional and three-dimensional ferroelectric capacitors from micro-focused synchrotron X-ray techniques

• Published in: Journal of applied crystallography 2006-06, Vol.39 (3), p.376-384
• Main Authors: Menou, N., Muller, Ch, Goux, L., Barrett, R., Lisoni, J. G., Schwitters, M., Wouters, D. J.
• Format: Article
• Language: English
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Dielectric, piezoelectric, ferroelectric and antiferroelectric materials; Dielectrics, piezoelectrics, and ferroelectrics and their properties; Exact sciences and technology; ferroelectric capacitors; ferroelectric random access memory; micro-focused synchrotron X-ray diffraction; micro-focused synchrotron X-ray fluorescence; microelectronic devices; Niobates, titanates, tantalates, pzt ceramics, etc; Physics
• ISSN: 1600-5767; 0021-8898; 1600-5767
• DOI: 10.1107/S002188980601082X

Future development of ferroelectric random access memory requires the integration of three‐dimensional ferroelectric capacitors (FeCAP) in a microelectronic architecture. In this paper, pin‐shaped two‐dimensional and three‐dimensional Sr0.8Bi2.2Ta2O9‐based FeCAP arrays were characterized using an original approach combining micro‐focused synchrotron X‐ray fluorescence and diffraction. From a modelling approach, dimensional, chemical and microstructural details were extracted over a series of capacitor arrays. Hence, these techniques proved insightful for a non‐destructive benchmarking approach. In addition, for all investigated capacitor geometries, the micro‐fluorescence experiments evidenced a well controlled chemical composition within the FeCAP arrays, attesting the stability of the elaboration and integration steps. Nevertheless, micro‐diffraction experiments have indicated a lower control of the ferroelectric film crystallographic orientation from one capacitor to the next, despite a well defined chemical composition. This feature was attributed to the presence of patterned bottom electrodes, bringing to light the role of the slanted capacitor sidewalls in the three‐dimensional geometry and partially explaining the non‐optimized electrical polarization usually measured in three‐dimensional capacitors with respect to planar geometry.