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

The Institute of Electronics and Information Engineers (대한전자공학회)
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The Fabrication of MOS Capacitor composed of $HfO_2$/Hf Gate Dielectric prepared by Atomic Layer Deposition

ALD 방법으로 증착된 $HfO_2$/Hf 박막을 게이트 절연막으로 사용한 MOS 커패시터 제조

  • Lee, Dae-Gab (Dept. of Electronics Engineering, Kyungpook national University) ;
  • Do, Seung-Woo (Dept. of Electronics Engineering, Kyungpook national University) ;
  • Lee, Jae-Sung (Division of Information and Communication Engineering, Uiduk University) ;
  • Lee, Yong-Hyun (Dept. of Electronics Engineering, Kyungpook national University)
  • 이대갑 (경북대학교 전자공학과) ;
  • 도승우 (경북대학교 전자공학과) ;
  • 이재성 (위덕대학교 정보통신공학부) ;
  • 이용현 (경북대학교 전자공학과)
  • Published : 2007.05.25
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Abstract

In this paper, $HfO_2$/Hf stacked film has been applied as the gate dielectric in MOS devices. The $HfO_2$ thin film was deposited on p-type (100) silicon wafers by atomic layer deposition (ALD) using TEMAHf and $O_3$ as precursors. Prior to the deposition of the $HfO_2$ film, a thin Hf metal layer was deposited as an intermediate layer. Round-type MOS capacitors have been fabricated on Si substrates with 2000${\AA}$-thick Al or Pt top electrode. The prepared film showed the stoichiometric components. At the $HfO_2$/Si interface, both Hf-Si and Hf-Si-O bonds were observed, instead of Si-O bond. The sandwiched Hf metal layer suppressed the growing of $SiO_x$ layer so that $HfSi_xO_y$ layer was achieved. It seems that the intermediate Hf metal layer has a benefit for the enhancement of electric characteristics of gate dielectric in $HfO_2$/Si structure.

본 논문에서는 MOS 소자의 게이트 유전체로 사용될 고유전 박막으로 $HfO_2$/Hf 박막을 제조하여 그 전기적 특성을 관찰하였다. $HfO_2$박막은 TEMAH와 $O_3$ 전구체를 사용한 ALD 방법으로 p-type (100) 실리콘 웨이퍼 위에 증착하였다. $HfO_2$막을 증착시키기 전에 중간층으로써 Hf 금속 층을 증착하였다. Round-type의 MOS 커패시터 제작을 위해, 상부 전극은 Al 또는 Pt을 이용하여 약 2000 ${\AA}$ 두께의 전극을 형성하였다. $HfO_2$ 박막은 화학정량적 특성을 보였으며, $HfO_2$/Si 계면에서 Si-O 결합 대신 Hf-Si 결합과 Hf-Si-O 결합이 관찰되었다. $HfO_2$와 Si 사이의 Hf 중간층은 $SiO_x$의 성장이 억제되었고, $HfSi_xO_y$으로 변형되었다. 이러한 결과로 $HfO_2$/Hf/Si 구조에서 Hf 중간층이 있음으로 게이트 유전체의 고유전율이 유지되면서 계면 특성이 개선됨을 확인하였다.

Keywords

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