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Novel High-Q Suspended Inductors on Alumina Ceramic Substrates

Published online by Cambridge University Press:  01 February 2011

Lisa Woodward
Affiliation:
Gennum Corporation, 970 Fraser Drive, Burlington, Ontario L7L 5P5, Canada Dept. of Electrical and Computer Engineering, University of Waterloo, 200 University Ave. W., Waterloo, Ontario N2L 3G1, Canada
Paul Woo
Affiliation:
Gennum Corporation, 970 Fraser Drive, Burlington, Ontario L7L 5P5, Canada
Mircea Capanu
Affiliation:
Gennum Corporation, 970 Fraser Drive, Burlington, Ontario L7L 5P5, Canada
Ivo Koutsaroff
Affiliation:
Gennum Corporation, 970 Fraser Drive, Burlington, Ontario L7L 5P5, Canada
C. R. Selvakumar
Affiliation:
Dept. of Electrical and Computer Engineering, University of Waterloo, 200 University Ave. W., Waterloo, Ontario N2L 3G1, Canada
Andrew Cervin-Lawry
Affiliation:
Gennum Corporation, 970 Fraser Drive, Burlington, Ontario L7L 5P5, Canada
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Abstract

The growth of the wireless industry over the past ten years has created a need for good quality passive components, and in particular high Q factor inductors. There has been a large amount of work aimed at improving the quality factors of inductors on both silicon and ceramic/insulating substrates. KAIST and other research groups have explored a MEMS technique, releasing the inductor coil to create an air gap between the coil and underpass, on silicon [1]. Typically the inductor coil has been separated by a 50 to 100μm air gap and has required special processing such as a dual exposure photoresist mold [1]. In the present work, suspended inductor coils have been fabricated and characterized on an alumina ceramic substrate [2]. The gap used was only 1μm and this was enough to increase the self-resonance frequency by up to 4GHz after release. The inductor coils were created in 6–10μm thick electroplated gold and the underpass in an aluminum layer. A sacrificial LPCVD oxide layer was used as the released dielectric. In the present study a range of inductance from 1 to 30nH was explored before and after release. The Q factors achieved in this work range from 40 to 70 in the 2 to 10 GHz range, which are some of the best Q factors reported for planar inductors (see Table I). In addition, since the architecture allowed the use of three metal layers, released transformers were also fabricated. They showed promising high frequency performance, which also will be presented. Minimum insertion loss better then –2dB was achieved between 10–12 GHz. The above described process is simple, precise, and manufacturable with the ability to extend the useful range of inductors to higher frequencies (1–10 GHz).

Type
Research Article
Copyright
Copyright © Materials Research Society 2005

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References

REFERENCES

[1] Yoon, J.-B. et al, “CMOS-Compatible Surface Micromachined Suspended-Spiral Inductors for Multi-GHz Silicon RF Ics,” IEEE Electron Device Lett., vol. 23, pp. 591593, Oct. 2002.Google Scholar
[2] Cervin Lawry, A. at al, “Development of a Miniature Bluetooth Module for Manufacturability using a System-in-Package Approach,” Ceramic Interconnect Technology: Next Generation, Proceedings of the Society of Photo-Optical Instrumentation Engineers (SPIE), vol. 5231, pp. 711, 2003.Google Scholar
[3] Meyer, R.G., Niknejad, , Design, Ali M., Simulation and Applications of Inductors and Transformers for Si RF ICs. Kluver Academic Publishers: Boston, 2000.Google Scholar
[4] Pieters, P. et al, “High-Q Integrated Spiral Inductors for High Performance Wireless Front-End Systems,” Radio and Wireless Conference 2000 (RAWCON 2000), pp. 251254, Sept. 2000.Google Scholar
[5] Ozgur, M. et al, “High Q Backside Micromachined CMOS Inductors,” IEEE, pp. II577–II-580, 1999.Google Scholar
[6] Merrill, R.B. et al, “Optimization of High Q Integrated Inductors for Multi-Level Metal CMOS,” IEDM 95, pp. 983986, 1995.Google Scholar
[7] Yoon, J.-B., et al, “CMOS-Compatible Surface-Micromachined Suspended-Spiral Inductors for Multi-GHz Silicon RF ICs,” IEEE Electron Device Lett., vol. 23, pp. 591593, Oct. 2002.Google Scholar
[8] Niknejad, A.M. and R.G., Meyer, “Analysis, Design, and Optimization of Spiral Inductors and Transformers for Si RF IC's,” IEEE Journal of Solid-State Circuits, vol. 33, pp. 14701481, Oct. 1998.Google Scholar