Strengthening TiN diffusion barriers for Cu metallization by lightly doping Al

Yang, L C; Hsu, C S; Chen, G S; Fu, C C; Zuo, J M; Lee, B Q

doi:10.1063/1.2056583

Title: Strengthening TiN diffusion barriers for Cu metallization by lightly doping Al

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Abstract

Thin films of Ti{sub 1-x}Al{sub x}N were deposited on (100) Si by ultrahigh-vacuum dual-target reactive sputtering, and the impact of lightly doping Al of x as small as 0.09 on altering the films's microstructure upon thermal annealing, and hence the performance of the films (40 nm thick) as diffusion barriers for Cu metallization was evaluated. The results of transmission electron microscopy, Rutherford backscattering spectroscopy, and grazing-incidence x-ray diffraction show that the TiN barrier layer gives the commonly observed voided, columnar grains composed of 5 nm sized subgrains. Upon annealing, the subgrains tend to coalesce into 20 nm sized equiaxed grains full of crystalline defects, initiating an inward penetration of Cu and a partial dissociation of TiN, transforming themselves, respectively, into pyramidal (or columnar) Cu{sub 3}Si precipitates and a dendritic Ti{sub 5}Si{sub 3} layer just after 550 deg. C, 10 min annealing. However, the lightly doped Al not only overrides the tendency to form intercolumnar voids inherent in sputter deposition by self-shadowing and statistical roughening, but also substantially enhances the microstructural and thermochemical stability, hence significantly improving barrier property, as evidenced from an annealing test at an elevated temperature (600 deg. C) for a prolonged period of 30 min.

Authors:

Yang, L C; Hsu, C S; Chen, G S; Fu, C C; Zuo, J M; Lee, B Q ^[1]

Department of Materials Science and Engineering, National Formosa University, Yunlin 632, Taiwan (China)

Publication Date:: Mon Sep 19 00:00:00 EDT 2005

OSTI Identifier:: 20709791

Resource Type:: Journal Article

Journal Name:: Applied Physics Letters

Additional Journal Information:: Journal Volume: 87; Journal Issue: 12; Other Information: DOI: 10.1063/1.2056583; (c) 2005 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0003-6951

Country of Publication:: United States

Language:: English

Subject:: 36 MATERIALS SCIENCE; ALUMINIUM; ANNEALING; COPPER; COPPER SILICIDES; CRYSTAL DEFECTS; DENDRITES; DIFFUSION BARRIERS; DISSOCIATION; DOPED MATERIALS; MICROSTRUCTURE; PRECIPITATION; RUTHERFORD BACKSCATTERING SPECTROSCOPY; SPUTTERING; TEMPERATURE DEPENDENCE; TEMPERATURE RANGE 0400-1000 K; THIN FILMS; TITANIUM NITRIDES; TITANIUM SILICIDES; TRANSMISSION ELECTRON MICROSCOPY; X-RAY DIFFRACTION

Citation Formats


                    Yang, L C, Hsu, C S, Chen, G S, Fu, C C, Zuo, J M, Lee, B Q, Department of Materials Science and Engineering, Feng Chia University, Taichung 407, Taiwan, and Department of Materials Science and Engineering, University of Illinois, Urbana, Illinois 61801. Strengthening TiN diffusion barriers for Cu metallization by lightly doping Al.  United States: N. p., 2005. 
        Web.  doi:10.1063/1.2056583.

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                    Yang, L C, Hsu, C S, Chen, G S, Fu, C C, Zuo, J M, Lee, B Q, Department of Materials Science and Engineering, Feng Chia University, Taichung 407, Taiwan, & Department of Materials Science and Engineering, University of Illinois, Urbana, Illinois 61801. Strengthening TiN diffusion barriers for Cu metallization by lightly doping Al.  United States.  https://doi.org/10.1063/1.2056583

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                    Yang, L C, Hsu, C S, Chen, G S, Fu, C C, Zuo, J M, Lee, B Q, Department of Materials Science and Engineering, Feng Chia University, Taichung 407, Taiwan, and Department of Materials Science and Engineering, University of Illinois, Urbana, Illinois 61801. 2005.  
        "Strengthening TiN diffusion barriers for Cu metallization by lightly doping Al".  United States.  https://doi.org/10.1063/1.2056583.

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@article{osti_20709791,

  title        = {Strengthening TiN diffusion barriers for Cu metallization by lightly doping Al},

  author       = {Yang, L C and Hsu, C S and Chen, G S and Fu, C C and Zuo, J M and Lee, B Q and Department of Materials Science and Engineering, Feng Chia University, Taichung 407, Taiwan and Department of Materials Science and Engineering, University of Illinois, Urbana, Illinois 61801},

  abstractNote = {Thin films of Ti{sub 1-x}Al{sub x}N were deposited on (100) Si by ultrahigh-vacuum dual-target reactive sputtering, and the impact of lightly doping Al of x as small as 0.09 on altering the films's microstructure upon thermal annealing, and hence the performance of the films (40 nm thick) as diffusion barriers for Cu metallization was evaluated. The results of transmission electron microscopy, Rutherford backscattering spectroscopy, and grazing-incidence x-ray diffraction show that the TiN barrier layer gives the commonly observed voided, columnar grains composed of 5 nm sized subgrains. Upon annealing, the subgrains tend to coalesce into 20 nm sized equiaxed grains full of crystalline defects, initiating an inward penetration of Cu and a partial dissociation of TiN, transforming themselves, respectively, into pyramidal (or columnar) Cu{sub 3}Si precipitates and a dendritic Ti{sub 5}Si{sub 3} layer just after 550 deg. C, 10 min annealing. However, the lightly doped Al not only overrides the tendency to form intercolumnar voids inherent in sputter deposition by self-shadowing and statistical roughening, but also substantially enhances the microstructural and thermochemical stability, hence significantly improving barrier property, as evidenced from an annealing test at an elevated temperature (600 deg. C) for a prolonged period of 30 min.},

  doi          = {10.1063/1.2056583},

  url          = {https://www.osti.gov/biblio/20709791},
  journal      = {Applied Physics Letters},

  issn         = {0003-6951},

  number       = 12,

  volume       = 87,

  place        = {United States},

  year         = {Mon Sep 19 00:00:00 EDT 2005},

  month        = {Mon Sep 19 00:00:00 EDT 2005}

}

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