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Korea Institute of Electronic Communication Science (한국전자통신학회)
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Effects of Working Pressure on Structural and Optical Properties of HfO2 Thin Films

공정 압력이 HfO2 박막의 구조적 및 광학적 특성에 미치는 영향

  • 정양희 (전남대학교 전기 및 반도체공학과) ;
  • 강성준 (전남대학교 전기 및 반도체공학과)
  • Received : 2017.09.27
  • Accepted : 2017.12.15
  • Published : 2017.12.31
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Abstract

The structural properties of $HfO_2$ films could be improved by calibrating the working pressure owing to the enhanced quality of a thin film. We deposited $HfO_2$ films on glass substrates by radio frequency (RF) magnetron sputtering under a base vacuum pressure lower than $4.5{\times}10^{-6}Pa$, RF power of 100 W, substrate temperature of $300^{\circ}C$. The working pressures were varied from 1 mTorr to 15 mTorr. Subsequently, their structural and optical properties were investigated. In particular, the $HfO_2$ film deposited at 1 mTorr had superior properties than the others, with a crystallite size of 10.27 nm, surface roughness of 1.173 nm, refractive index of 2.0937 at 550 nm, and 84.85 % transmittance at 550 nm. These results indicate that the $HfO_2$ film deposited at 1 mTorr is suitable for application in transparent electric devices.

$HfO_2$ 박막은 공정압력을 조정함으로써 박막의 질을 향상시켜 그 구조적 특성을 개선시킬 수 있다. 본 연구에서는 RF 마그네트론 스퍼터링 방법을 이용하여 유리 기판 위에 $HfO_2$ 박막을 증착하였으며, 이때의 기저 진공 압력은 $4.5{\times}10^{-6}Pa$ 이하였으며 RF 파워는 100 W, 기판의 온도는 $300^{\circ}C$ 이었다. 해당 박막 증착 공정의 공정 압력은 1 mTorr 에서 15 mTorr 로 변화되었다. 그 후, 해당 박막의 구조적 및 광학적 특성들을 조사하였다. 특히, 1 mTorr 의 공정 압력으로 증착된 $HfO_2$ 박막이 다른 박막들과 비교하여 가장 우수한 특성을 가진 것으로 나타났으며, 이때의 결정립의 크기는 10.27 nm, 표면 거칠기는 1.173 nm, 550 nm 파장에서의 굴절률은 2.0937, 그리고 550 nm 파장에서의 투과율은 84.85 % 의 우수한 특성을 나타내었다. 이러한 결과들을 통해 1 mTorr 의 공정 압력으로 증착된 $HfO_2$ 박막은 투명 전자 소자에 적용하기에 적합함을 알 수 있다.

Keywords

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