Journal of the Korean Crystal Growth and Crystal Technology (한국결정성장학회지)

The Korea Association of Crystal Growth (한국결정성장학회)
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Analysis of calcium fluoride single crystal grown by the czochralski method

초크랄스키 방법으로 성장한 CaF2 단결정 분석

  • Lee, Ha-Lin (Department of Advanced Materials Engineering, Dong-Eui University) ;
  • Na, Jun-Hyuck (Department of Advanced Materials Engineering, Dong-Eui University) ;
  • Park, Mi-Seon (Department of Advanced Materials Engineering, Dong-Eui University) ;
  • Jang, Yeon-Suk (Department of Advanced Materials Engineering, Dong-Eui University) ;
  • Jung, Hea-Kyun (SELIG) ;
  • Kim, Doo-Gun (KOPTI) ;
  • Lee, Won-Jae (Department of Advanced Materials Engineering, Dong-Eui University)
  • 이하린 (동의대학교 신소재공학과) ;
  • 나준혁 (동의대학교 신소재공학과) ;
  • 박미선 (동의대학교 신소재공학과) ;
  • 장연숙 (동의대학교 신소재공학과) ;
  • 정해균 ;
  • 김두근 ;
  • 이원재 (동의대학교 신소재공학과)
  • Received : 2022.11.02
  • Accepted : 2022.11.28
  • Published : 2022.12.31
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Abstract

CaF2 single crystal has a large band gap (12 eV), and it is used for optical windows, prisms, and lenses due to its excellent transmittance in a wide wavelength range and low refractive index. Moreover, it is expected to be one of the materials for ultraviolet transmissive laser optical components. CaF2 belongs to the fluoride compounds and has a face-centered cubic (FCC) structure with three sub-lattices. The representative method for CaF2 single crystal growth is Czochralski, which method has the advantages of high production efficiency and the ability to make large crystals. In this study, X-ray diffraction (XRD), X-ray rocking curves (XRC) measurement, and chemical etching were performed to analyze the crystallinity and defect density of the CaF2 single crystals, grown by the Czochralski method. Fourier-transform infrared spectroscopy (FT-IR) and UV-VIS-NIR spectroscopy systems were used to investigate the optical properties of the CaF2 crystal. The provability of various applications, including UV application, was systematically investigated with various analysis results.

광학 윈도우, 프리즘, 렌즈 등에 사용되는 CaF2 단결정은 3개의 부격자를 가진 face-centered cubic(FCC) 구조를 가지고 있으며 밴드갭(12 eV)이 크고 넓은 파장영역에서 투과율이 우수하고 굴절률이 낮다는 특징이 있다. CaF2 단결정 성장은 대표적으로 높은 생산효율과 큰 결정을 만들 수 있는 초크랄스키(Czochralski) 방법으로 생산되고 있다. 이 연구에서는 초크랄스키 방법으로 성장한 일본의 Nikon 사와 미국의 M TI 사 (100)면, (111)면의 CaF2 단결정 상용화 웨이퍼의 결정성과 결함밀도를 분석하기 위해 X선 회절(XRD), XRC(X-ray rocking curve) 측정 및 Chemical Etching을 수행하였고 푸리에 변환 적외선 분광법(FT-IR)과 UV-VIS-NIS을 이용하여 CaF2 결정의 광학적 특성을 분석하였다. 다양한 분석 결과를 통해 CaF2 단결정의 다양한 분야에서의 응용가능성을 체계적으로 살펴보았다.

Keywords

Acknowledgement

이 연구는 2022년 정부(산업통상자원부)의 재원으로 한국산업기술평가관리원의 지원(20017105)과 교육부의 재원으로 한국기초과학지원연구원 국가연구시설장비진흥센터의 지원(No. 2019R1A6C1010045)과 2022년 정부(산업통상자원부)의 재원으로 한국산업기술진흥원의 지원(P0012451, 2022년 산업혁신인재성장지원사업)의 지원을 받아 수행된 연구입니다.

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