Journal of the Institute of Electronics Engineers of Korea SD (대한전자공학회논문지SD)

The Institute of Electronics and Information Engineers (대한전자공학회)
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The study of RF gain reduction due to air-bridge for CPW PHEMT's

CPW PHEMT의 에어브리지에 의한 이득 감소 현상에 대한 연구

  • 임병옥 (동국대학교 밀리미터파 신기술연구센터) ;
  • 강태신 (동국대학교 밀리미터파 신기술연구센터) ;
  • 이복형 (동국대학교 밀리미터파 신기술연구센터) ;
  • 이문교 (동국대학교 밀리미터파 신기술연구센터) ;
  • 이진구 (동국대학교 밀리미터파 신기술연구센터)
  • Published : 2003.12.01
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Abstract

To analyze the effects of the air-bridge parasitic capacitances on the performance of coplanar waveguide pseudomorphic high electron mobility transistors (CPW PHEMTs), the gate-to-air-bridge ( $C_{ag}$ ) and the drain-to air-bridge ( $C_{ad}$ ) capacitances were taken into account plus the conventional pinched-off cold. FET circuit model. To examine the effects of the parasitic capacitances due to the air-bridges, a variety routing schemes for the air-bridge interconnection were adopted for fabricating the 0.1-${\mu}{\textrm}{m}$ $\Gamma$-gate length CPW HEMT's. According to air-bridge schemes, the $S_{21}$ gain is affected considerably. From the results of the fabricated CPW PHEMT, the $C_{ag}$ and $C_{ad}$ is one of the important factor of decreasing the gain of HEMTs.

에어브리지의 기생 커패시턴스의 영향을 분석하기 위해 CPW PHEMT의 기존 cold-FET 회로모델에 게이트-에어브리지의 기생 커패시턴스(C/sub ag/)차 드레인-에어브리지의 기생 커패시턴스(C/sub ad/)를 더해주었다. 또한 제안된 모델을 사용하여 소자의 parameter들을 추출하여, 그 존재를 확인하였다. 본 논문에서는 에어브리지에 의해 생성되는 기생 커패시턴스의 영향을 연구하기 위해 에어브리지의 여러 연결방법을 CPW PHEMT 제작에 접목시켰다. 또한 핀치오프상태의 cold-FET에 대한 개선된 등가회로 모델을 제시하여 에어브리지에 의한 기생 커패시턴스가 소자 특성에 어떤 영향을 주는 가를 분석하였다. 제작된 CPW PHEMT의 측정 결과로부터, 기생 커패시턴스 C/sub ag/와 C/sub ad/가 소자의 S/sub 21/ 이득을 감소시키는 중요한 요소임을 확인하였다.

Keywords

References

  1. Gilles Dambrine, Alain Cappy, Frederic Heliodore and Edouard Playez, 'A New Method for Determining the FET Small-signal Equivalent Circuit', IEEE Trans. Microwave Theory and Tech., vol. 36, no. 7, pp. 1151-1159, July 1988 https://doi.org/10.1109/22.3650
  2. P. M. White and R. M. Healy, 'Improved equivalent circuit of GaAs FETs for determination of MESFET and HEMT parasitic capacitances from Coldfet measurements', IEEE Microwave and Guided Wave Lett., vol, 3, no. 12, pp.453-454, Dec. 1993 https://doi.org/10.1109/75.251398
  3. Hiroshi Ohta, Takuma Tanimoto, Jsao Ohbu, Katsuhiko Higuchi, Shinichiro Takatani, Naoyuki Kurita, Keigo Kamozaki and Hiroshi Kondoh, 'High-performance HEMT with an Offset-Gate Structure for Millimeter-Wave Monolithic Microwave ICs', Jpn. J. Appl. Phys., vol. 37, no. 3B, pp 1373-1376, Mar, 1998 https://doi.org/10.1143/JJAP.37.1373
  4. Tae-Sin Kang, Seong-Dae Lee, Bok-Hyoung Lee, Sam Dong Kim, Hyun-Chang Park, Hyung-Moo Park, and Jin-Koo Rhee, 'Design and Fabrication of a Low-Noise Amplifier for the V-band', Journal of the Korean Physical Society., vol. 41, no. 4, pp. 533-538, Oct. 2002
  5. R. Anholt and S. Swirhun, 'Equivalent-circuit parameter extraction for cold GaAs MESFETs', IEFE Trans. Microwave Theory and Tech., vol. 39, no. 7, pp. 1243-1247, July 1991 https://doi.org/10.1109/22.85396
  6. A. Eskandarian and S. Weinreb, 'A note on experimental determination of small -signal equivalent circuit of millimeter wave FETs', IEEE Trans. Microwave Theory and Tech., vol. 41, no. 7, pp. 159-162, Jan. 1993 https://doi.org/10.1109/22.210247
  7. R. Anholt and S. Swirhun, 'Measurement and Analysis of GaAs MESFET Parasitic Capacitances', IEEE Trans. Microwave Theory and Tech., vol. 39, no. 7, pp. 1243-1247, July 1991 https://doi.org/10.1109/22.85396
  8. Yeong-Lin Lai and Kuo-Hua Hsu, 'A New Pinched Off Cold-FET Method to Determine Parasitic Capacitances of FET Equivalent Circuits', IEEE Trans. Microwave Theory and Tech., vol. 49, no. 8, pp. 1410-1418, Aug. 2001 https://doi.org/10.1109/22.939921
  9. Woo-Suk Sul, Byeong-Ok Lim, Seong-Dae Lee, Dong-Hoon Shin, Sam-Dong Kim, Soon-Koo Kim, Yong-Hoh Kim and Jin-Koo Rhee, 'Stduies on the fabrication of $0.1_{\mu}\;{\Gamma}$-gate PHEMT's', Proceedings of ITC-CSCC '01, Tokushima, Japan, pp. 1017-1021, 2001
  10. J.W. Shin, Y.S. Yoon, S.D. Lee, H.C. Park, and J.K. Rhee, 'Effects of He gas on hydrogen content and passivation of GaAs PHEMT with SIN films', 2000 Asia Pacific Workshop on Fundamental and Application of Advanced Semiconductor Devices(AWAD), pp. 121-124, 2000
  11. Seong Dae Lee, Dan An, Hyung Moo Park, Hyun Chang Park, Sam Dong Kim, and Jin Koo Rhee, 'Analysis of characteristics of PHEMT's fabricated by gate recess methods', 2002. Asia-Pacific Workshop on Fundamental and Application of Advanced Semiconductor Devices, pp. 119-204, 2002