University of Oulu

Mikko Nelo, Timo Vahera, Tuomo Siponkoski, Jari Juuti, and Heli Jantunen , "Ultra-low permittivity ULTCC composite materials" , Applied Physics Letters 118, 142901 (2021)

Ultra-low permittivity ULTCC composite materials

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Author: Nelo, Mikko1; Vahera, Timo1; Siponkoski, Tuomo1;
Organizations: 1Microelectronics Research Unit, P. O. Box 4500, FI-90014, University of Oulu, Finland
Format: article
Version: accepted version
Access: open
Online Access: PDF Full Text (PDF, 0.7 MB)
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Language: English
Published: American Institute of Physics, 2021
Publish Date: 2021-05-04


A method to realize ultra-low temperature co-fireable ceramic composites with ultra-low permittivity is presented in this work. Hollow glass microspheres with size of 10—100 μm were used as a filler in a tape based on lithium molybdate (Li2MoO4) ceramic to introduce controlled porosity and reduce the relative permittivity of the sintered product. A lamination pressure of only 1.25 MPa was sufficient to produce samples with uniform structure and without delamination. Differential scanning calorimetry and thermogravimetric analysis were used to optimize the sintering temperature profile of the material. The microstructure of the samples was investigated with FESEM and the dielectric properties with a split post dielectric resonator (SPDR). Compatibility of the composite ceramic with silver was tested by applying thick film printed electrodes and post-firing them on the surface. Samples sintered at 540 °C exhibited a relative permittivity of 1.4—5.40 and a loss tangent of 10-3—10-4 at 5 and 10 GHz. The method shows interesting possibilities to significantly reduce processing temperatures compared to conventional LTCC materials and to obtain the extremely low permittivity that is especially required for future high frequency applications.

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Series: Applied physics letters
ISSN: 0003-6951
ISSN-E: 0003-6951
ISSN-L: 0003-6951
Volume: 118
Issue: 14
Article number: 142901
DOI: 10.1063/5.0048566
Type of Publication: A1 Journal article – refereed
Field of Science: 213 Electronic, automation and communications engineering, electronics
216 Materials engineering
114 Physical sciences
116 Chemical sciences
Funding: The work leading to these results received funding from the European Research Council (ERC) under the ERC POC Grant Agreement No. 812837. This work was supported in part by the Academy of Finland 6Genesis Flagship (Grant No. 318927), Printed Intelligence Infrastructure (PII) (Grant No. 320017), and in part by the European Regional Development Fund project ‘Novel digitally fabricated materials for electronics, optics and medical applications (NOVIDAM)’, Grant No. A74080.
EU Grant Number: (812837) FUNCOMP - Fabricating Functional Components in Room Temperature
Copyright information: © 2021 Author(s). Published under license by AIP Publishing. The Definitive Version of Record can be found online at: