Oxide Films for Integrated Capacitors in Thin Film Functional Modules

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OXIDE FILMS FOR INTEGRATED CAPACITORS IN THIN FILM FUNCTIONAL MODULES M. Klee*, D. Wissen*, W. Keur**, R. Kiewitt*, D. Bausen*, P. Lok***, * Philips GmbH Forschungslaboratorien Aachen, Weißhausstr. 2, 52066 Aachen, Germany, [email protected] ** Philips Research Laboratories Eindhoven, P.O. BOX *** Philips Discrete Semiconductors, Nijmegen ABSTRACT Single oxide films as well as complex oxide films are intensively studied for multi-chip modules with integrated passive functions. In this paper the processing and properties of oxide films such as Ta2O5, TiO2, Nb2O5, Ta2O5 -Al2O3, Ta2O5–Nb2O5 as well as complex oxide films such as BiNbO4 and Ba1-xSrxTiO3 films will be discussed with respect to their integration into thin film functional modules. INTRODUCTION Ceramic oxide films are a revolution in the electro-ceramic industry. The integration of ferroelectric thin films into semiconductor processes is the basis for a new class of memories such as ferroelectric non-volatile memories (FERAMs). The high performance of oxide films, which has been achieved in the last years as well as the progress in integration technologies offers high density functional modules [1-11]. To apply oxide thin films in miniaturised and integrated high performance devices, thin films have to be tuned with respect to their special applications. In the following, the processing and the electric properties of oxide thin films will be discussed, especially, with respect to their dielectric properties in integrated capacitors. HIGH PERFORMANCE FUNCTIONAL MODULES For high functionality portable electronic systems such as mobile communication and wireless data transfer systems, new product concepts are requested, that enable the integration of passive functions (capacitors, resistors, inductors) with active functions into high performance multifunctional modules. Various concepts are developed: • Thick Film Technologies • Ceramic Co-firing Processes (MCM-C) • Laminate Technologies (MCM-L) • Thin Film Multi-chip Modules (MCM-D) Thin film functional modules with a planar integration of e.g matching circuits, filtering circuits next to active functions such as amplifying stages. on top of Si or Al2O3 are on the market. To achieve a high degree of integration also three-dimensional integrated modules have been demonstrated, see ref. [1]. Dielectric thin films with a temperature coefficient of the capacitance of ± 60 or ± 30 ppm/K For applications such as integrated matching circuits, thin film capacitors are requested, that show a very stable capacitance over a large temperature range. Thin film capacitors have to be developed that offer a temperature stability of the capacitance of ± 60 or ± 30 ppm/K, if CC13.1.1

heated up from –55oC up to 125oC (so called COH or COG specifications). One dielectric thin film material with a temperature coefficient of the capacitance of ± 30 ppm/K, is SiN(H). SiN(H) with a relative permittivity of 6.5 gives limitations in the integration of large capacitance values. Thin films in the systems Ta2O5, TiO2, Nb2O5, Ta2