Damages of etched BST films by high density plasmas

고밀도 플라즈마에 의한 BST 박막의 damage에 관한 연구

  • 최성기 (중앙대학교 전자전기공학부) ;
  • 김창일 (중앙대학교 전자전기공학부) ;
  • 장의구 (중앙대학교 전자전기공학부) ;
  • 서용진 (대불대학교 정보공학부) ;
  • 이우선 (조선대학교 전기제어계측공학부)
  • Published : 2000.11.01

Abstract

High dielectric (Ba,Sr)TiO$_3$ thin films were etched in an inductively coupled plasma (ICP) as a function of C1$_2$/Ar gas mixing ratio. Under Cl$_2$(20)/Ar(80), the maximum etch rate of the BST films was 400$\AA$/min and selectivities of BST to Pt and PR were obtained 0.4 and 0.2, respectively. We investigated the etched surface of BST by x-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and x-ray diffraction (XRD). From the result of XPS analysis, we found that residues of Ba-Cl and Ti-Cl bonds remained on the surface of the etched BST for high boiling point. The surface roughness decreased as Cl$_2$ increases in Cl$_2$/Ar plasma because of non-volatile etching products. This changed the nature of the crystallinity of BST. From the result of XRD analysis, the crystalliility of etched BST film maintained as similar to as-deposited BST under Ar only and Cl$_2$(20)/Ar(80). However, (100) orientation intensity of etched BST film abruptly decreased at Cl$_2$ only plasma. It was caused that Cl compounds were redeposited on the etched BST surface and damaged to crystallinity of BST film during the etch process.

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