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

The Institute of Electronics and Information Engineers (대한전자공학회)
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Analysis and Optimization of the CMOS Transistors for RF Applications with Various Channel Width and Length

CMOS 트랜지스터의 채널 폭 및 길이 변화에 따른 RF 특성분석 및 최적화

  • 최정기 (韓國情報通信大學院大學校 工學部) ;
  • 이상국 (韓國情報通信大學院大學校 工學部) ;
  • 송원철 (韓國電子通信硏究員)
  • Published : 2000.08.01
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Abstract

MOS transistors are fabricated and evaluated for RF IC applications such as mobile communication systems using 0.35m CMOS process. Characteristics of MOSFETs are analyzed at various channel length, width and bias conditions. From the analysis, cut-off frequency ($f_T$) is independent on channel width but maximum oscillation frequency ($f_{max}$) tends to derease as the channel width increases. As channel length increases, $f_T$ and fmax decrease. $f_T$ is 22GHz and fmax is 28GHz at its maximum value. High frequency noise performance is improved with larger channel width and smaller channel length at same bias conditions. NFmin at 2GHz is 0.45dB as a minimum value. From the evaluation, MOSFETs designed using 0.35m CMOS process demonstrated a full potential for the commercial RF ICs for mobile communication systems near 2GHz. And optimization methods of the CMOS transistors for RF applications are presented in this paper.

0.35m CMOS공정을 이용하여 MOSFET의 RF특성을 평가하였다. 채널길이(L-0.25~0.8m)와 채널폭(W=50~600m) 및 바이어스 전압의 변화에 따른 RF특성을 분석하였으며, 차단주파수$f_T$는 최대 22GHz, 최대공진주파수($f_{max}$)는 최대 28GHz의 값을 얻었다. 채널폭의 변화에 대해서 차단주파수는 영향을 받지 않았으며, 최대공진주파수는 감소하는 경향을 보였고, 채널길이 증가에 대해서는 차단주파수 및 최대공진주파수 모두 감소하는 경향을 나타내었다. 최소잡음지수는 채널폭이 증가할수록 감소하고 채널길이가 증가할수록 증가하는 경향을 얻었는데, 2GHz에서 최소 0.45dB의 값을 얻었다. 평가결과로부터 0.35m CMOS공정이 2GHz대역의 상업용 RFIC 구현에 충분한 RF특성을 보유하고 있음을 확인할 수 있었으며, 바이어스 및 채널폭과 길이변화에 대한 CMOS 트랜지스터의 RF 특성분석을 통하여 RF 회로설계에 대한 지침을 제시하였다.

Keywords

References

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