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Negative ions in reactive magnetron sputtering
Author(s) -
Welzel Thomas,
Ellmer Klaus
Publication year - 2013
Publication title -
vakuum in forschung und praxis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.213
H-Index - 13
eISSN - 1522-2454
pISSN - 0947-076X
DOI - 10.1002/vipr.201300518
Subject(s) - sputtering , ion , oxide , materials science , cavity magnetron , groove (engineering) , sputter deposition , secondary emission , analytical chemistry (journal) , deposition (geology) , atomic physics , optoelectronics , chemistry , thin film , metallurgy , nanotechnology , physics , paleontology , organic chemistry , sediment , biology , chromatography
Negative ions are present in magnetron sputtering if electronegative elements are involved. The majority of the negative ions impinging on transparent conductive oxide (TCO) films during growth is O − produced at the oxidised target surface while it is rather unimportant whether it is bulk oxide or a surface oxide formed in reactive sputtering. O − bombards the film with energies equivalent to the target voltage and by far exceed 100 eV. It is hence apt to cause radiation damage in sensitive TCO films. This is shown by the lateral distribution of the highenergy O − flux in planar magnetron sputtering that exhibits the same pattern imaging the erosion groove as the resistivity of TCO films. This lateral inhomogeneity strongly depends on the erosion groove depth. The emission of O − further depends on the sputtered material, for TiO 2 deposition it is much less than for other TCO materials. The emission probability correlates to the secondary electron emission coefficient of the oxide.