Etching characteristics and mechanism of Ba0.7Sr0.3TiO3 thin films in an inductively coupled plasma

Dong Sing Wuu*, Fang Ching Liao, Nei Hao Kuo, Ray-Hua Horng, Ming Kwei Lee

*Corresponding author for this work

Research output: Contribution to journalArticle

19 Scopus citations

Abstract

The inductively-coupled-plasma (ICP) etching behavior of B0.7Sr0.3TiO3 (BST) thin films has been characterized with Cl2/CF4, Cl2/SF6 and Cl2/Ar gas mixtures. CF4 and SF6 were found to impede the etch process, presumably due to competition between plasma deposition and etching. A chemically assisted etch of BST was obtained under various Cl2/Ar gas mixtures. The etch profile along with etch anisotropy was observed as a function of etching parameters by scanning electron microscopy. The surface morphologies after etching were analyzed by atomic force microscopy. A smooth surface (roughness ∼1.8nm) with no residue was observed under 30%Cl2 in Ar/Cl2, ICP power of 1 kW, substrate bias of 500V, and 10mTorr. To clarify the etching mechanism, the surface reaction of the BST thin films was investigated by X-ray photoelectron spectroscopy. It was found that Ba was mainly removed by chemically assisted physical etching (possible products such as BaClx). Physical bombardment is more effective than Cl chemical reaction for removing Sr, while Ti can almost be removed by chemical reaction (such as TiClx). The etching results described correlate well with the thermochemical calculations.

Original languageEnglish
Pages (from-to)2068-2072
Number of pages5
JournalJapanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers
Volume39
Issue number4 B
DOIs
StatePublished - Apr 2000

Keywords

  • BST
  • DRAM
  • Dry etching
  • Etching mechanism
  • Inductively coupled plasma

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