Metrological characterization of nanometer film thickness standards for XRR and ellipsometry applications

Hasche, K.; Thomsen-Schmidt, Peter; Krumrey, Michael; Ade, G.; Ulm, G.; Stuempel, J.; Schaedlich, Stefan; Frank, W.; Procop, M.; Beck, Uwe

doi:10.1117/12.512216

Cited by 14 publications

(9 citation statements)

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“…These results are consistent with the results reported earlier in the literature. 6,9 A comparison of the thickness values observed for well-characterized Ta 2 O 5 films using SE and XRR are shown in Fig. 4.…”

Section: Resultsmentioning

confidence: 99%

“…Hasche et al had used a photon energy of 1841 eV for XRR measurements, which is just above the Si K-edge absorption. 9 At these energies the authors found sufficient contrast between the electron densities of both materials and the results were reported with low uncertainties. Clearly the SiO 2 /Si system is not a material of choice for metrological characterization of nanometer film thickness standards using frequently employed laboratory x-ray sources that can be used with high throughput thin film deposition processes.…”

Section: Introductionmentioning

confidence: 95%

“…͑3͒ had been based on some comprehensive studies performed by authors on SiO 2 layers deposited on Si substrate. 9 As we discuss below, SiO 2 /Si is clearly not a system of choice for this comparison work in the laboratory.…”

Section: Introductionmentioning

confidence: 99%

“…They had attributed the nonzero intercepts to the adsorption of hydrocarbon contaminants on the native silicon oxide layer of the silicon substrates for the a-C : H surfaces. 8 In a recent attempt at metrological characterization of nanometer film thickness standards for XRR and SE applications using 6-1000 nm SiO 2 layer on Si substrate, Hasche et al 9 had reported higher values of thickness measured using SE than XRR. They had a͒ Author to whom correspondence should be addressed; electronic mail: skohli@lamar.colostate.edu also found that the XRR measurements were consistent with the thickness estimation by scanning force microscopy.…”

Section: Introductionmentioning

confidence: 99%

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Comparison of nanometer-thick films by x-ray reflectivity and spectroscopic ellipsometry

Kohli

Rithner

Dorhout

et al. 2005

Review of Scientific Instruments

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Films of tantalum pentoxide ͑Ta 2 O 5 ͒ with thickness of 10-100 nm were deposited on Si wafers and have been compared using spectroscopic ellipsometry ͑SE͒ and x-ray reflectivity ͑XRR͒. ͑Ta 2 O 5 ͒ was chosen for comparison work based on various criterions for material selection outlined in this article. Measurements were performed at six positions across the sample area to take into consideration thickness and composition inhomogeneity. SE and XRR fitted curves required the incorporation of a linearly graded interface layer. SE systematically measured higher values of film thickness as compared to XRR. A linear equation was established between the thickness measurements using SE and XRR. The slope of the linear equation established was found to be 1.02± 0.01. However, the intercepts were found to be 1.7± 0.2 and 2.6± 0.3 when the interface was excluded and included, respectively. These differences in the values of intercepts were attributed to the uncertainties in the determination of the interface layer.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 95%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Comparison of nanometer-thick films by x-ray reflectivity and spectroscopic ellipsometry

Kohli

Rithner

Dorhout

et al. 2005

Review of Scientific Instruments

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“…X-ray reflectometry is widely used for characterizing the thickness, roughness, and density of nanometer scale thin films. Because it uses wavelengths of a similar or smaller scale relative to the thicknesses of the layers being studied, the resulting data has a relatively direct connection to the structure and therefore has a rather straightforward traceability to the International System of Units (SI) [1,2,3]. This is a significant advantage over other techniques like spectroscopic ellipsometry (SE), whose results are somewhat more difficult to interpret.…”

Section: Introductionmentioning

confidence: 99%

Limitations of x-ray reflectometry in the presence of surface contamination

Gil¹

2012

J. Phys. D: Appl. Phys.

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Intentionally deposited thin films exposed to atmosphere often develop unintentionally deposited few monolayer films of surface contamination. This contamination arises from the diverse population of volatile organics and inorganics in the atmosphere. Such surface contamination can affect the uncertainties in determination of thickness, roughness and density of thin film structures by X-Ray Reflectometry (XRR). Here we study the effect of a 0.5 nm carbon surface contamination layer on thickness determination for a 20 nm titanium nitride thin film on silicon. Uncertainties calculated using Markov-Chain Monte Carlo Bayesian statistical methods from simulated data of clean and contaminated TiN thin films are compared at varying degrees of data quality to study (1) whether synchrotron sources cope better with contamination than laboratory sources and (2) whether cleaning off the surface of thin films prior to XRR measurement is necessary. We show that, surprisingly, contributions to uncertainty from surface contamination can dominate uncertainty estimates, leading to minimal advantages in using synchrotronover laboratory-intensity data. Further, even prior knowledge of the exact nature of the surface contamination does not significantly reduce the contamination's contribution to the uncertainty in the TiN layer thickness. We conclude, then, that effective and standardized cleaning protocols are necessary to achieve high levels of accuracy in XRR measurement.

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Polysaccharide Thin Films – Preparation and Analysis

Sampl¹,

Spirk²

2023

Functional Biomaterials

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Metrological characterization of nanometer film thickness standards for XRR and ellipsometry applications

Cited by 14 publications

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Comparison of nanometer-thick films by x-ray reflectivity and spectroscopic ellipsometry

Comparison of nanometer-thick films by x-ray reflectivity and spectroscopic ellipsometry

Limitations of x-ray reflectometry in the presence of surface contamination

Polysaccharide Thin Films – Preparation and Analysis

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