Surfaces, Thin Films and Coatings

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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.

Section: Depth Profiling Analysis Of Ultrathin Filmsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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

Shimizu

Habazaki

Skeldon

et al. 2003

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“…For non-conductive materials, glow discharge sputtering rates have been shown to be dependent on the matrix and the sample thickness. 6,7 It should be noted that the signal profile for Ti is rather surprising, thus the Ti oxide layer is the thinnest layer but the signal for Ti lasted for >90 s. Although the rate of r.f. glow discharge sputtering is known to vary with the chemical composition of the sample, the differences in sputtering rates are unlikely to explain this pattern.…”

Section: Schott Glassmentioning

confidence: 99%

Surface characterization and depth profile analysis of glasses by r.f. GDOES

Coustumer¹,

Motelica-Heino²,

Chapon³

et al. 2003

The characterization of surfaces, interfaces and interphases in glasses is analytically challenging and may benefit from recent developments in radiofrequency glow discharge optical emission spectroscopy (r.f. GDOES) applied to non-conductive materials. Thus, the main thrust of this study is to evaluate the potential of r.f. GDOES for the characterization of glass surfaces, physical heterogeneities such as discrete layers and continuous interphases and the distribution of elements in glass materials. Model glasses with increasing structural and chemical complexity thus were analysed using a Jobin Yvon GDOES system (5000 RF): the glasses included a multilayered glass (triple-coated glass), two photoreactive glasses (with potential chemical diffusion gradients) and acid-leached glass with an alteration layer. Concurrently, surface characterization of the glasses was conducted using scanning electron microscopy or transmission electron microscopy with energy-dispersive x-ray imaging to assess the chemical and physical gradients in the materials and to investigate the glow discharge sputtering process. From this the capability of r.f. GDOES for elemental depth profiling in glass materials is established. However, although the sputtering rates for glass are greatly reduced compared with conductive materials (∼2 nm s −1 compared with 50-150 nm s −1 for metals), r.f. GDOES offers good spatial depth resolution (nm) and elemental sensitivity for several applications, such as the characterization of interfaces or interphases and the determination of chemical gradients in glasses. Furthermore, the technique distinguishes submicrometre discrete layers in the coated glass, and the diffusion of elements within glass matrices may be monitored.

“…The most successful r.f. mode to date for CDP of a wide variety of materials is constant pressure and constant power, 19 possibly because until recently it has been the only mode routinely available. But it may be that in future different modes will be optimal for different applications, e.g.…”

Section: Modes Of Operationmentioning

confidence: 99%

New aspects of quantification in r.f. GDOES

Payling

Michler

Aeberhard

et al. 2003

Quantification algorithms for radiofrequency glow discharge optical emission spectroscopy (r.f. GDOES) calibration and analysis are briefly reviewed. These include corrections for emission yield, self-absorption, spectral interferences and relative sputtering rates. The emission yield term is then expanded to allow variable power calibration. The use of sputter factors to determine relative sputtering rates is explored. Finally, pulsed r.f. operation is considered and compared with continuous power operation in an alloy steel calibration and in the qualitative depth profile of a heat-sensitive coated glass.