Origin and Effects of Negative Ions in the Sputtering of Intermetallic Compounds

Cuomo, J. J.; Gambino, R. J.; Harper, J. M. E.; Kuptsis, J. D.

doi:10.1147/rd.216.0580

Cited by 47 publications

(19 citation statements)

References 4 publications

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“…3, i.e., smooth surface roughness was observed for the films grown with oxygen in the sputtering ambient. Even though the I − EA could not be an absolute standard value of resputtering, the I − EA value of ITO was about 4.36 eV when the value was gathered from the previous studies [22][23][24], which signifies that the resputtering effect might not be such a serious problem in ITO system. From these points of view, even though resputtering might have partly contribute to ITO system, it has not predominantly affected the surface characteristics of ITO.…”

Section: Methodsmentioning

confidence: 86%

“…3, a very rough surface was observed in the (400) Concerning the momentum transfer of oxygen, the resputtering effect has been studied in sputtering-assisted oxide thin film growth, in which negative oxygen ions are frequently formed [20][21][22][23][24][25][26]. Cuomo et al suggested that if the value of I − EA (I: ionization potential, EA: electron affinity) were less than 3.4 eV, they predicted a negative ion formation, and the presence of resputtering effects [22,23]. A subsequent study by Kester et al [24] showed that the negative ion resputtering became stronger as the I − EA value decreased.…”

Section: Methodsmentioning

confidence: 99%

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Effects of oxygen partial pressure on the preferential orientation and surface morphology of ITO films grown by RF magnetron sputtering

et al. 2007

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In this study, effects of oxygen pressure in the sputtering ambient on the preferential orientation and resultant surface morphology of ITO films grown by RF magnetron sputtering were investigated. ITO film grown with pure Ar gas shows a preferential (400) plane orientation parallel to the substrate surface and a sawteethshaped rough surface. ITO film grown in the sputtering ambient of Ar and oxygen mixtures shows a preferential (222) plane orientation and a flat and smooth surface. The differences in the growth rate, surface morphology, and roughness between the preferentially orientated films were discussed in terms of the surface energy of planes. The electrical and optical properties of the films were examined.

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Section: Methodsmentioning

confidence: 86%

Section: Methodsmentioning

confidence: 99%

Effects of oxygen partial pressure on the preferential orientation and surface morphology of ITO films grown by RF magnetron sputtering

et al. 2007

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“…The first systematic approach followed from the observation of etching instead of film growth during diode sputtering of binary compounds of Au and rare earth elements by Cuomo et al 33 They attributed the etching to Au-bombardment of the film during sputtering and developed a model based on the electron affinity, EA B , of one target constituent B (Au) acting as acceptor and the ionization potential, I PA , of the other constituent A acting as donor. In this model, the formation of negative ions is preferred when donation is likely (low I PA ) and acceptance is high (high EA B ).…”

Section: Model Comparison Of the Overall O 2 Fluxmentioning

confidence: 99%

Negative oxygen ion formation in reactive magnetron sputtering processes for transparent conductive oxides

Welzel¹,

Ellmer²

2012

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

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Reactive d.c. magnetron sputtering in Ar/O2 gas mixtures has been investigated with energy-resolved mass spectrometry. Different metal targets (Mg, Ti, Zn, In, InSn, and Sn), which are of importance for transparent conductive oxide thin film deposition, have been used to study the formation of negative ions, mainly high-energetic O−, which are supposed to induce radiation damage in thin films. Besides their energy distribution, the ions have been particularly investigated with respect to their intensity in comparison of the different target materials. To realize the comparability, various calibration factors had to be introduced. After their application, major differences in the negative ion production have been observed for the target materials. The intensity, especially of O−, differs by about two orders of magnitude. It is shown that this difference results almost exclusively from ions that gain their energy in the target sheath. Those may gain additional energy from the sputtering process or reflection at the target. Low-energetic negative ions are, however, less affected by changes of the target material. The results concerning O− formation are discussed in term of the sputtering rate from the target and are compared to models for negative ion formation.

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“…Research on negative ion resputtering ͑NIR͒ has been reported by Cuomo et al 14,15 and by Kester and Messier, 16 -18 but has often been ignored in discussions of sputter deposition. NIR involves the generation of negative ions (O Ϫ ) in proximity to the target's surface.…”

Section: Introductionmentioning

confidence: 99%

Influence of negative ion resputtering on ZnO:Al thin films

Rieth

Holloway

2003

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

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The influence of negative ion resputtering (NIR) by oxygen ions during sputter deposition of aluminum doped zinc oxide (ZnO:Al) thin films is investigated. A planar rf diode sputter deposition source with a ceramic ZnO:Al2O3 (98 wt %:2 wt %) target is used for deposition at 250, 500 and 1000 W. The resulting thin films are characterized by four point probe, Hall measurements, secondary ion mass spectrometry (SIMS), x-ray diffraction (XRD), and atomic force microscopy (AFM). The resistivity and carrier concentration show an order of magnitude variation between 2×10−2 and 1.5×10−3 Ω cm and 7.2×1019 and 5.4×1020 cm−3, respectively, with the position on the substrate and deposition power. The Hall mobility changes are small, from 4.7 to 11.5 cm2/V s. Data from SIMS show that the variations in electrical properties do not result from contamination by alkali metals or changes in the Al dopant concentration. Spectra from XRD have one predominant peak near 34.4° indicating that the film is wurtzite and strongly textured in the (002) basal direction. All peaks are lower in 2θ than literature values, which indicates an expanded lattice in the c direction. Grain size estimates based on AFM data suggest that changes in grain size are not large enough to cause the changes in electrical properties. Compensation of free carriers by interstitial oxygen ions due to implantation and Frenkel pair generation resulting from an energetic oxygen ion flux are consistent with the data, and are postulated to be the mechanisms by which NIR influences the electrical properties of ZnO. The flux of negative ions is estimated to be 1% of the total ion flux. The correlation between NIR and the influence of deposition parameters is discussed.

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Origin and Effects of Negative Ions in the Sputtering of Intermetallic Compounds

Cited by 47 publications

References 4 publications

Effects of oxygen partial pressure on the preferential orientation and surface morphology of ITO films grown by RF magnetron sputtering

Effects of oxygen partial pressure on the preferential orientation and surface morphology of ITO films grown by RF magnetron sputtering

Negative oxygen ion formation in reactive magnetron sputtering processes for transparent conductive oxides

Influence of negative ion resputtering on ZnO:Al thin films

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