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

The Institute of Electronics and Information Engineers (대한전자공학회)
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3D Simulation on Polarization Effect in AlGaN/GaN HEMT

AlGaN/GaN HEMT의 분극 현상에 대한 3D 시뮬레이션

  • Jung, Kang-Min (School of Electrical Engineering, Korea University) ;
  • Kim, Jae-Moo (School of Electrical Engineering, Korea University) ;
  • Kim, Hee-Dong (School of Electrical Engineering, Korea University) ;
  • Kim, Dong-Ho (School of Electrical Engineering, Korea University) ;
  • Kim, Tae-Geun (School of Electrical Engineering, Korea University)
  • 정강민 (고려대학교 전자전기공학과) ;
  • 김재무 (고려대학교 전자전기공학과) ;
  • 김희동 (고려대학교 전자전기공학과) ;
  • 김동호 (고려대학교 전자전기공학과) ;
  • 김태근 (고려대학교 전자전기공학과)
  • Received : 2009.10.26
  • Accepted : 2010.04.27
  • Published : 2010.10.25
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Abstract

In this paper, we investigated the polarization effects on the electrical and structural characteristics of AlGaN/GaN HEMT. Both the Al mole-fraction and the barrier thickness of AlGaN, which determine the profiles of a two-dimensional electron gas, were simulated to obtain the optimum HEMT structure affecting the polarization effect. As a results, we found that the amount of bound sheet charges was increased by 16% and the maximum drain current density ($I_D$,max) was increased by more than 37%, while AI mole fractions are changed from 0.3 to 0.4. We also observed a 37% improvement in maximum drain current density ($I_D$,max) by increasing AIGaN layer thickness from 17 to 38 nm. However when AlGaN layer thickness reached the critical thickness, DC characteristics were dramatically lowered due to 'bulk' relaxation in AlGaN layer.

본 논문에서는 AlGaN/GaN HEMT의 분극에 의한 전기적인 특성과 구조적인 특성에 대해서 분석하였다. 몰 분율, AlGaN barrier 층의 두께의 물리적인 변화에 따라서 이차원 전자가스 채널의 농도 변화가 이루어지는 것을 바탕으로 DC 특성 및 분극을 고려한 최적화된 구조에 대해서 시뮬레이션을 진행하였다. AlGaN의 몰 분율이 0.3 몰에서 0.4 몰로 증가할수록 분극에 의한 bound sheet charge가 16 % 증가하며 그에 따라서 Id-Vd 특성 역시 37% 증가하게 된다. 또한 AlGaN 층의 두께가 17 nm에서 38nm로 증가할수록 Id-Vd의 특성이 증가하다가 임계두께인 39nm에 이르게 되면 AlGaN층의 relaxation에 의해서 급격하게 특성이 나빠지는 것을 알 수 있다.

Keywords

References

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