Defects and morphological changes in nanothin Cu films on Mo(100) studied by thermal helium desorption spectrometry

Venugopal, Vinay; Seijbel, Léon J.; Pers, N. M. van der; Thijsse, Barend J.

doi:10.1063/1.1794360

Cited by 5 publications

(6 citation statements)

References 36 publications

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“…This is less than the activation energy of 1.2± 0.1 eV obtained for island formation in the case of 100 Å Cu on Mo͑100͒. 4 Finally, additional information about the origin of the M peak can be obtained from spectrum 10 Å Cu, which was obtained after implanting 1000 eV helium into a 10 Å Cu film deposited on Mo ͑no annealing͒. The fact that the M peak is seen in 300-982 K but not in 10 Å Cu strongly suggests that the helium released in the M peak comes from the island regions of the Cu film and not from the thin regions.…”

Section: A Effect Of Annealingmentioning

confidence: 63%

“…3͒ and Mo͑100͒. 4 It was observed 4 that the Cu films for the same thickness responded differently to the process of island formation and to sublimation. In this section we compare the 75 eV helium-implanted film thickness variation series of the Cu films on poly-Mo with those on Mo͑110͒ and Mo͑100͒.…”

Section: H Effect Of Substrate Orientationmentioning

confidence: 98%

“…The desorption peaks E, F, G, and H have been identified earlier 15,16 and were also observed in our previous work. 3,4 They are caused by the following helium-defect reactions ͑V denotes a vacancy, and He * a mobile helium atom͒: E peak ͑820 K͒: He n V → He * + He n−1 V ͑n = 5 -8͒, F peak ͑950 K͒: He n V → He * + He n−1 V ͑n = 3 -4͒, G peak ͑1010 K͒: He 2 V → He * + HeV, H peak ͑1200 K͒: HeV → He * + V.…”

Section: A Effect Of Annealingmentioning

confidence: 99%

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Defects and morphological changes in nanothin Cu films on polycrystalline Mo analyzed by thermal helium desorption spectrometry

Venugopal

Seijbel

Thijsse

2005

Journal of Applied Physics

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Thermal helium desorption spectrometry ͑THDS͒ has been used for the investigation of defects and thermal stability of thin Cu films ͑5 -200 Å͒ deposited on a polycrystalline Mo substrate in ultrahigh vacuum. These films are metastable at room temperature. On heating, the films transform into islands, giving rise to a relatively broad peak in the helium desorption spectra. The temperature of this island formation is dependent on film thickness, being 417 K for 10 Å and 1100 K for a 200 Å film. The activation energy for island formation was found to be 0.3± 0.1 eV for 75 Å film. Grain boundaries have a strong effect on island formation. The defect concentration in the as-deposited films is ϳ5 ϫ 10 −4 , for films thicker than 50 Å and more for thinner films. Helium release from monovacancies was identified in the case of a 200 Å film. Helium release was also seen during sublimation of the Cu film ͑ϳ1350 K͒. Overlayer experiments were used to identify helium trapped close to the film surface. An increase of the substrate temperature during deposition resulted in a film that had already formed islands. Argon-ion assistance ͑250 eV͒ during film deposition with an ion/atom ratio of ϳ0.1 resulted in a significant enhancement of helium trapping in the films. The argon concentration in the films was found to be 10 −3 . The temperature of island formation was increased due to argon-ion assistance. The helium and argon desorption spectra are found to be similar, which is due to most of the helium becoming trapped in the defects created by the argon beam. The role of the Mo surface in affecting the defects at the film-substrate interface is investigated. The effect of variation of helium fluence and helium implantation energy is also considered. The present THDS results of Cu/poly-Mo are compared to those of Cu/ Mo͑100͒ and Cu/ Mo͑100͒ reported earlier.

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Section: A Effect Of Annealingmentioning

confidence: 63%

Section: H Effect Of Substrate Orientationmentioning

confidence: 98%

Section: A Effect Of Annealingmentioning

confidence: 99%

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Defects and morphological changes in nanothin Cu films on polycrystalline Mo analyzed by thermal helium desorption spectrometry

Venugopal

Seijbel

Thijsse

2005

Journal of Applied Physics

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“…Investigations of defects in metal on metal heteroepitaxial systems have been rather limited and we consider defects in Cu/Mo(1 1 0) such as vacancies and vacancy clusters that can trap helium. Earlier we have reported a THDS study of Cu films on Mo(1 0 0) [17] and polycrystalline Mo [18] substrates.…”

Section: Introductionmentioning

confidence: 99%

“…Analysis of the helium desorption signal as a function of sample temperature yields information on defects, film coverage and ion damage effects [17,18] . For a detailed THDS study of the helium-defect interactions in Cu films grown on Mo(1 1 0), we have therefore varied deposition conditions such as film thickness, post-deposition annealing temperature, post-implantation overlayer thickness and helium implantation energy.…”

Section: Introductionmentioning

confidence: 99%

Defects of ultrathin Cu films on Mo(1 1 0) studied by thermal helium desorption spectrometry

Venugopal¹,

Thijsse²

2009

J. Phys. D: Appl. Phys.

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Defects of ultrathin Cu films (3-200 Å) deposited on Mo(1 1 0) at room temperature by e-beam evaporation in ultra-high vacuum are investigated using thermal helium desorption spectrometry. The samples are analysed with both 75 and 1000 eV He + implantation. Cu films transform into islands on annealing and the temperature of this transformation is strongly thickness dependent. Helium release from defects close to the surface of the Cu films (∼450 K), from monovacancies in as-deposited Cu film (50-200 Å), and from defects close to the interface (800-1050 K) are identified. Annealing of monovacancies is mainly responsible for reduction in helium trapping in a 20 Å Cu film prior to film islanding. There is an indication of retrapping of helium released from the first 5 Å layer of the film in the defects located in the overlayers (5-95 Å). Helium in the Cu films survives until the desorption temperature of the film (1200-1300 K).

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Study of defects and thermal stability of ultrathin Cu films on Ta(110) and Ta(100) by thermal helium desorption spectrometry

Venugopal

Thijsse

2009

Thin Solid Films

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Defects and morphological changes in nanothin Cu films on Mo(100) studied by thermal helium desorption spectrometry

Abstract: Defects and morphological changes in nanothin Cu films on polycrystalline Mo analyzed by thermal helium desorption spectrometry

Cited by 5 publications

References 36 publications

Defects and morphological changes in nanothin Cu films on polycrystalline Mo analyzed by thermal helium desorption spectrometry

Defects and morphological changes in nanothin Cu films on polycrystalline Mo analyzed by thermal helium desorption spectrometry

Defects of ultrathin Cu films on Mo(1 1 0) studied by thermal helium desorption spectrometry

Study of defects and thermal stability of ultrathin Cu films on Ta(110) and Ta(100) by thermal helium desorption spectrometry

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