Journal of the Microelectronics and Packaging Society (마이크로전자및패키징학회지)

The Korean Microelectronics and Packaging Society (한국마이크로전자및패키징학회)
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Electrical Properties of Two-dimensional Electron Gas at the Interface of LaAlO3/SrTiO3 by a Solution-based Process

용액 공정을 통해 제조된 LaAlO3/SrTiO3 계면에서의 이차원 전자 가스의 전기적 특성

  • Kyunghee Ryu (Department of Materials Science and Engineering Hongik University) ;
  • Sanghyeok Ryou (Department of Energy Systems Research, Ajou University) ;
  • Hyeonji Cho (Department of Materials Science and Engineering Hongik University) ;
  • Hyunsoo Ahn (Department of Physics, Inha University) ;
  • Jong Hoon Jung (Department of Physics, Inha University) ;
  • Hyungwoo Lee (Department of Energy Systems Research, Ajou University) ;
  • Jung-Woo Lee (Department of Materials Science and Engineering Hongik University)
  • 유경희 (홍익대학교 나노신소재학과) ;
  • 유상혁 (아주대학교 에너지시스템학과) ;
  • 조현지 (홍익대학교 나노신소재학과) ;
  • 안현수 (인하대학교 물리학과) ;
  • 정종훈 (인하대학교 물리학과) ;
  • 이형우 (아주대학교 에너지시스템학과) ;
  • 이정우 (홍익대학교 나노신소재학과)
  • Received : 2024.03.15
  • Accepted : 2024.03.29
  • Published : 2024.03.30
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Abstract

The discovery of a two-dimensional electron gas (2DEG) at the interface of LaAlO3 (LAO) and SrTiO3 (STO) substrates has sparked significant interest, providing a foundation for cutting-edge research in electronic devices based on complex oxide heterostructures. However, conventional methods for producing LAO thin films, typically employing techniques like pulsed laser deposition (PLD) within physical vapor deposition (PVD), are associated with high costs and challenges in precisely controlling the La and Al composition within LAO. In this study, we adopted a cost-effective alternative approach-solution-based processing-to fabricate LAO thin films and investigated their electrical properties. By adjusting the concentration of the precursor solution, we varied the thickness of LAO films from 2 to 65 nm and determined the sheet resistance and carrier density for each thickness. After vacuum annealing, the sheet resistance of the conductive channel ranged from 0.015 to 0.020 Ω·s-1, indicating that electron conduction occurs not only at the LAO/STO interface but also into the STO bulk region, consistent with previous studies. These findings demonstrate the successful formation and control of 2DEG through solution-based processing, offering the potential to reduce process costs and broaden the scope of applications in electronic device manufacturing.

SrTiO3 (STO) 기판 위에 성장된 LaAlO3 (LAO) 계면에서의 이차원 전자 가스 (2DEG)의 발견은 복합 산화물 이종 구조를 기반으로 한 혁신적인 전자소자 연구의 장을 제공함으로써 많은 관심을 받아왔다. 하지만 LAO 박막을 형성하기 위하여, 일반적으로 물리기상증착법(PVD)을 기반으로 하는 펄스 레이저 증착 (PLD) 등의 기법이 주로 사용되어 왔으나, 공정 비용이 많이 들며 LAO 내 La와 Al의 정밀한 조성 제어가 어려운 단점이 있다. 본 연구에서는 PVD에 비해 경제적인 대안인 용액 기반 공정을 사용하여 LAO 박막을 제조하였고, 그 전기적 특성을 평가하였다. LAO 전구체 용액의 농도를 다르게 하여 LAO의 두께를 2에서 65 nm까지 변화시켰으며, 각 두께에 따른 면저항 및 캐리어 농도를 도출하였다. 진공 열처리 후 형성된 전도성 채널의 면저항 값은 0.015에서 0.020 Ω·sq-1 범위로 나타났으며, 이러한 결과는 기존 문헌과 비교하였을 때 LAO와 STO 사이의 계면에서의 전자 이동뿐만 아니라 계면으로부터 떨어져 있는 STO bulk 영역으로의 전자 전도를 시사한다. 본 연구 결과는 용액 기반 공정을 통한 2DEG 형성 및 제어를 구현한 것으로, 공정 비용을 줄이고 전자 소자 제조에서 보다 광범위한 응용 가능성을 제시한다는 점에 그 의의가 있다.

Keywords

Acknowledgement

본 연구는 홍익대학교 신임교수 연구지원비에 의하여 지원되었음.

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