Transmission Grating Formation in High Refractive-index Amorphous Thin Films Using Focused-Ion-Beam Lithography

접속이온빔 리소그라피를 이용한 고굴절 비정질 박막 투과 격자 형성

  • 신경 (광운대 공대 전자재료공학과) ;
  • 김진우 (광운대 공대 전자재료공학과) ;
  • 박정일 (광운대 공대 전자재료공학과) ;
  • 이현용 (일본 동북대 금속재료연구소) ;
  • 이영종 (여주대 전자과) ;
  • 정홍배 (광운대 공대 전자재료공학과)
  • Published : 2001.01.01

Abstract

In this study, we investigated the optical properties of sub-wavelength a-Si thin film transmission gratings, especially the polarization effect, the phase difference and the birefringence by using linearly polarized He-Ne laser beam (632.8nm). The a-Si transmission grating of the thickness $of < 0.1 \mum$ with four-type period($\Lambda = 0.4 \mum and 0.6 \mum$ for sub-wavelength and $\Lambda = 1.0 \mum and 1.4 \mum$ for above-wavelength) on quartz substrates have been fabricated using 50 KeV Ga+ Focused-Ion-Beam(FIB) Milling and $CF_4$Reactive-Ion-Etching(RIE) method. Finally, we obtained the trating array of a-Si thin film with a period $0.4 \mum, 0.6 \mum, 1.0 \mum, 1.4 \mum$ which have nearly equal finger spacing and width, sucessfully. Especially, for gratings with $\Lambda = 0.6 \mum(linewidth=0.25 \mum, linespace=0.35\mum), the \etamax at \theta_в=17.0^{\circ}$ is estimated to be 96%. As the results, we believe that the sub-wavelength grating arrayed a-Si thin film has the applicability as the optical device and components.

Keywords

References

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