Design and Fabrication of RF MEMS Switch by the CMOS Process

Ching-Liang  Dai; Hsuan-Jung Peng; Mao-Chen Liu; Chyan-Chyi Wu; Lung-Jieh Yang

doi:10.6180/jase.2005.8.3.03

Design and Fabrication of RF MEMS Switch by the CMOS Process

Ching-Liang Dai This email address is being protected from spambots. You need JavaScript enabled to view it.¹, Hsuan-Jung Peng¹ , Mao-Chen Liu¹ , Chyan-Chyi Wu² and Lung-Jieh Yang³

¹Department of Mechanical Engineering, National Chung Hsing University Taichung, Taiwan 402, R.O.C.
²Center for Measurement standards, Industrial Technology Research Institute, Hsinchu, Taiwan 300, R.O.C.
³Department of Mechnical and Electro-Mechanical Engineering, Tamkang University Tamsui, Taiwan 251, R.O.C.

Received: February 1, 2005
Accepted: April 15, 2005
Publication Date: September 1, 2005

Download Citation: ||https://doi.org/10.6180/jase.2005.8.3.03

ABSTRACT

This work investigates the fabrication of a RF (ratio frequency) MEMS (micro elector mechanical system) switch using the standard 0.35 m 2P4M (double polysilicon four metal) CMOS (complementary metal oxide semiconductor) process and the post-process. The switch is a capacitive type, which is actuated by an electrostatic force. The structure of the switch consists of a CPW (coplanar waveguides) transmission lines and a suspended membrane. The CPW lines and the membrane are the metal layers of the CMOS process. The main advantage of the RF switch is only needed a simple post-process, which is compatible with the CMOS process. The post-process uses an etchant, silox vapox III, to etch oxide layer to release the suspended membrane and springs. Experiment results show that the pull-in voltage of the switch is about 17 V. The insertion loss and return loss in the range of 10 to 40 GHz are –2.5 dB and 13 dB, respectively.

Keywords: CMOS, Post-process, MEMS, RF Switch

REFERENCES

[1] Yao, J. J., “RF MEMS from a Device Perspective,” J. Micromech. Microeng., Vol. 10, pp. R9–R38 (2000).
[2] Goldsmith, C., Randall, J., Eshelman, S., Lin, T. H., Denniston, D., Chen, S. and Norvell, B., “Characteristics of Micromachined Switches at Microwave Frequencies,” Microwave Symposium Digest, IEEE MTT-S International, Vol. 2, pp. 11411144 (1996).
[3] Petersen, K. E., “Micromechanical Membrane Switches on Silicon,” IBM J. Res. Develop., Vol. 23, pp. 376 385 (1979).
[4] Goldsmith, C. L., Yao, Z., Eshelman, S. and Denniston, D., “Performance of Low-loss RF MEMS Capacitive Switches,” Microwave and Guided Wave Letters, IEEE, Vol. 8, pp.269271 (1998).
[5] Park, J. Y., Kim, G. H., Chung, K. W. and Bu, J. U., “Monolithically Integrated Micromachined RF MEMS Capacitive Switches,” Sensors and Actuators A: Physical, Vol. 89, pp. 8894 (2001).
[6] Peroulis, D., Pacheco, S. P., Sarabandi, K. and Katehi, L. P. B., “Electromechanical Considerations in Developing Low-voltage RF MEMS Switches,” IEEE Trans. Microwave Theory Tech., Vol. 51, pp. 259270 (2003).
[7] Shen, S. C., Caruth, D. and Feng, M., “Broadband low Actuation Voltage RF MEM Switches,” Gallium Arsenide Integrated Circuit (GaAs IC) Symposium, 22nd Annual, pp. 161164 (2000).
[8] Mihailovich, R. E., Kim, M., Hacker, J. B., Sovero, E. A., Studer, J., Higgins, J. A. and DeNatale, J. F., “MEM Relay for Reconfigurable RF Circuits,” Microwave and Wireless Components Letters, IEEE, Vol. 11, pp. 53–55 (2001).
[9] Milanovi’c, V., Gaitan, M., Bowen, E. D., and Zaghloul, M. Z., “Micromachined Microwave Transmission Lines in CMOS Technology,” IEEE Trans. Microwave TheDesign and Fabrication of RF MEMS Switch by the CMOS Process 201 ory Tech., Vol. 45, pp. 630635 (1997).
[10] Dai, C. L., Xiao, F. Y., Juang, Y. Z. and Chiu, C. F., “An Approach to Fabricating Microstructures That Incorporate Circuits Using a post-CMOS Process,” J. Micromech. and Microeng., Vol. 15, pp. 98103 (2005).