Impurity distributions in barrier anodic films on aluminium: a GDOES depth profiling study

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Glow discharge mass spectrometry has been widely used for trace and ultra-trace element analysis of high-purity alloys. A novel pulsed radio frequency glow discharge time-of-flight mass spectrometer (rf GD TOFMS) has been developed that retains the pulsed radio frequency analytical ion source to provide ion signal enhancement due to processes involving Penning ionisation. A time-resolved detection mode has been implemented to sample the afterglow regime of the pulse profile, corresponding to the highest ion signal intensities. Here, the performance of rf GD TOFMS in isotope differentiation is discussed. Anodic tantala films, comprising 18 O-rich layers of controlled thicknesses and locations, were formed by appropriate combination of anodising of tantalum in electrolytes enriched with 18 O isotopes and of natural O isotopic abundance. Transmission electron microscopy (TEM) and radio frequency glow discharge optical emission spectrometry (rf GD OES) analyses were performed to examine the morphology and elemental distributions of the specimens, while the content of 18

Section: Time-resolved Detection Mode In Rf Glow Discharge Mass Spectmentioning

confidence: 99%

Section: Specimen Characterisationmentioning

confidence: 99%

Section: Specimen Characterisationmentioning

confidence: 99%

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¹⁸O/¹⁶O isotopic separation in anodic tantala films by glow discharge time‐of‐flight mass spectrometry

Tempez

Canulescu

Молчан

et al. 2009

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“…Phosphorus species, PO 3 4 , are present only in the outer half of the film, similar to anodic alumina films formed in neutral phosphate solutions. 18 In addition, GDOES shows copper enrichment in the metal just beneath the film. The specimen contained 30 ppm copper in a solid solution with aluminium.…”

Section: Depth Profiling Analysis Of Ultrathin Filmsmentioning

confidence: 99%

Radiofrequency GDOES: a powerful technique for depth profiling analysis of thin films

Shimizu

Habazaki

Skeldon

et al. 2003

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Previously, glow discharge optical emission spectroscopy (GDOES), both d.c. and r.f. has been used for depth profiling analysis of thick films several tens of microns thick, utilizing its high sputtering rates of >1 µm min −1 . Through selected examples, it is demonstrated here that r.f. GDOES also has enormous potential for depth profiling analysis of ultrathin films <10 nm thick, where AES and SIMS have dominant roles. The significant features of r.f. GDOES enabling such analysis arise from the nature of r.f. glow discharge sputtering where samples, both conducting and non-conducting, are sputtered very stably with Ar + ions of low energies .<50 eV) and high current fluxes (of the order of 100 mA cm −2 ). The low Ar + energy ensures that film sputtering proceeds without significant formation of altered layers, which is a prerequisite for successful depth profiling analysis of ultrathin films at high depth resolution. The high current fluxes allow sputtering to proceed at very high rates of >1 µm min −1 , thereby extending the limit of film thickness for analysis to 100 µm. Thus r.f. GDOES, with its unique ability to accommodate depth profiling analysis of films of a very wide thickness range, is expected to play an important role in the field of practical surface analysis.

“…The proportion of the thickness of the tungsten-containing region to the total film thickness is 0.29 that is in good agreement with data described elsewhere. [9] GD OES elemental depth profiling readily reveals the presence of the tungsten-containing outer film region (Fig. 2).…”

Section: Resultsmentioning

confidence: 99%

Differentiation of ¹⁸O‐ and ¹⁶O‐rich layers in anodic alumina films by glow discharge time‐of‐flight mass spectroscopy

Молчан

Thompson

Skeldon

et al. 2010

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