Journal of IKEEE (전기전자학회논문지)

Institute of Korean Electrical and Electronics Engineers (한국전기전자학회)
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Electrical Properties of Al2O3 Gate Oxide on 4H-SiC with Post Annealing Fabricated by Aerosol Deposition

에어로졸 데포지션으로 제조된 4H-SiC 위 Al2O3 게이트 산화막의 후열처리 공정에 따른 전기적 특성

  • Kim, Hong-Ki (National Institute for Nanomaterials Technology, Pohang University of Science and Technology (POSTECH)) ;
  • Kim, Seong-jun (National Institute for Nanomaterials Technology, Pohang University of Science and Technology (POSTECH)) ;
  • Kang, Min-Jae (National Institute for Nanomaterials Technology, Pohang University of Science and Technology (POSTECH)) ;
  • Cho, Myung-Yeon (Dept. of Electronic Materials Engineering, Kwangwoon University) ;
  • Oh, Jong-Min (Dept. of Electronic Materials Engineering, Kwangwoon University) ;
  • Koo, Sang-Mo (Dept. of Electronic Materials Engineering, Kwangwoon University) ;
  • Lee, Nam-suk (National Institute for Nanomaterials Technology, Pohang University of Science and Technology (POSTECH)) ;
  • Shin, Hoon-Kyu (National Institute for Nanomaterials Technology, Pohang University of Science and Technology (POSTECH))
  • Received : 2018.12.08
  • Accepted : 2018.12.23
  • Published : 2018.12.31
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Abstract

$Al_2O_3$ films with the thickness of 50 nm were fabricated on 4H-SiC by aerosol deposition, and their electrical properties were characterized with different post annealing conditions. As a result, the $Al_2O_3$ film annealed in $N_2$ atmosphere showed decreased fixed charge density at the interface area between the $Al_2O_3$ and SiC, and increased leakage currents due to the generation of oxygen vacancies. From this result, it was confirmed that proper $N_2$ and $O_2$ ratio for the post annealing process is important.

에어로졸 데포지션 (aerosol deposition)공정을 통해 $Al_2O_3$막을 4H-SiC 상에 50 nm 두께로 제조하였고, 후열처리 공정에 따른 전기적 특성을 분석하였다. 그 결과 $N_2$분위기 열처리 시 $Al_2O_3$와 SiC 계면의 고정전하량이 감소하였으나 산소공공 생성에 의한 누설전류의 증가를 확인하였다. 본 결과로부터 계면특성 향상과 누설전류의 감소를 위해서는 적절한 $N_2$와 $O_2$가스의 혼합이 중요함을 확인하였다.

Keywords

JGGJB@_2018_v22n4_1230_f0001.png 이미지

Fig. 1. (a) surface SEM image of as-deposited Al2O3 film. cross-sectional SEM images of (b) as-deposited, (c) air annealed, and (d) N2 annealed Al2O3 films, respectively. 그림 1. (a) 성막된 Al2O3 막 표면 SEM 이미지. Al2O3 막의 단면 SEM 이미지 (b) 열처리 전,（c) 대기분위기 열처리, (d) N2분위기 열처리.

JGGJB@_2018_v22n4_1230_f0002.png 이미지

Fig. 3. Dielectric properties of (a) as-deposited, (b) air annealed, and (c) N2 annealed Al2O3 films, respectively. 그림 3. (a) 열처리 전, (b) 대기분위기 열처리, (c) N2분위기 열처리 Al2O3 막의 유전특성

JGGJB@_2018_v22n4_1230_f0003.png 이미지

Fig. 4. Leakage currents of (a) as-deposited, (b) air annealed, and (c) N2 annealed Al2O3 films, respectively. 그림 4. (a) 열처리 전, (b) 대기분위기 열처리, (c) N2분위 기 열처리 Al2O3 막의 누설전류 특성

JGGJB@_2018_v22n4_1230_f0004.png 이미지

Fig. 2. High-frequency (1 MHz) C-V curves for (a) as-deposited, (b) air annealed, and (c) N2 annealed Al2O3 films, respectively. 그림 2. (a) 열처리 전, (b) 대기분위기 열처리, (c) N2분위기 열처리 Al2O3 막의 고주파 (1 MHz) C-V 그래프

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