Hostname: page-component-586b7cd67f-t7czq Total loading time: 0 Render date: 2024-11-22T17:08:35.478Z Has data issue: false hasContentIssue false
  • English
  • Français

The Accuracy of Al and Cu Film Thickness Determinations and the Implications for Electron Probe Microanalysis

Published online by Cambridge University Press:  27 April 2018

Mike B. Matthews ,
Stuart L. Kearns  and
Ben Buse
Mike B. Matthews*
Affiliation:
AWE, Aldermaston, Reading RG7 4PR, UK University of Bristol, School of Earth Sciences, Wills Memorial Building, Queens Road, Clifton BS8 1RJ, UK
Stuart L. Kearns
Affiliation:
University of Bristol, School of Earth Sciences, Wills Memorial Building, Queens Road, Clifton BS8 1RJ, UK
Ben Buse
Affiliation:
University of Bristol, School of Earth Sciences, Wills Memorial Building, Queens Road, Clifton BS8 1RJ, UK
*
Author for correspondence: Mike B. Matthews, E-mail: [email protected]
Get access

Abstract

The accuracy to which Cu and Al coatings can be determined, and the effect this has on the quantification of the substrate, is investigated. Cu and Al coatings of nominally 5, 10, 15, and 20 nm were sputter coated onto polished Bi using two configurations of coater: One with the film thickness monitor (FTM) sensor colocated with the samples, and one where the sensor is located to one side. The FTM thicknesses are compared against those calculated from measured Cu Lα and Al Kα k-ratios using PENEPMA, GMRFilm, and DTSA-II. Selected samples were also cross-sectioned using focused ion beam. Both systems produced repeatable coatings, the thickest coating being approximately four times the thinnest coating. The side-located FTM sensor indicated thicknesses less than half those of the software modeled results, propagating on to 70% errors in substrate quantification at 5 kV. The colocated FTM sensor produced errors in film thickness and substrate quantification of 10–20%. Over the range of film thicknesses and accelerating voltages modeled both the substrate and coating k-ratios can be approximated by linear trends as functions of film thickness. The Al films were found to have a reduced density of ~2 g/cm2.

Keywords

aluminumcopperbismuththin filmfilm thickness
Type
Materials Science Applications
Information
Microscopy and Microanalysis , Volume 24 , Issue 2 , April 2018 , pp. 83 - 92
Copyright
© Microscopy Society of America 2018 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Anderson, CA (1966) Electron probe microanalysis of thin layers and small particles with emphasis on light element determinations. In The Electron Microprobe, McKinley TD, Heinrich KFJ and Wittry DB (Eds.), pp. 58–74. New York: John Wiley and Sons Inc.Google Scholar
Bastin, GF, Dijkstra, JM, Heijligers, HJM, Klepper, D (1998) In-depth profiling with the electron probe microanalyzer. In Proceedings of EMAS ’98 3rd Regional Workshop, Llovet X and Salvat F (Eds.), pp. 25–55. Barcelona: Universitat de Barcelona.Google Scholar
Bastin, GF and Heijligers, HJM (2000 a) A systematic database of thin-film measurements by epma, part I – Aluminum films. Xray Spectrom 29(3), 212–238.3.0.CO;2-K>CrossRefGoogle Scholar
Bastin, GF and Heijligers, HJM (2000 b) A systematic database of thin-film measurements by EPMA, part II – Palladium films. Xray Spectrom 29(3), 373–397.3.0.CO;2-S>CrossRefGoogle Scholar
Bastin, GF and Heijligers, HJM (1991) Quantitative electron probe microanalysis of nitrogen. Scanning 13, 325–342.CrossRefGoogle Scholar
Blois, MS and Rieser, LM (1954) Apparent density of thin evaporated films. J Appl Phys 25(3), 338–340.CrossRefGoogle Scholar
Bottomley, PDW, Bremier, S, Glatz, JP, Walker, CT (2000) EPMA of melted UO2 fuel rods irradiated to a burn-up of 23 GWd/tU. Mikrochim Acta 132(2–4), 391–400.CrossRefGoogle Scholar
Campos, CS, Coleoni, EA, Trincavelli, JC, Kaschny, J, Hubbler, R, Soares, MRF, Vasconcellos, MAZ (2001) Metallic thin film thickness determination using electron probe microanalysis. Xray Spectrom 30, 253–259.CrossRefGoogle Scholar
Goldstein, J, Newbury, DE, Joy, DC, Lyman, CE, Echlin, P, Lifshin, E, Sawyer, L, Michael, JR (2003) Scanning Electron Microscopy and X-Ray Microanalysis Third. New York: Springer Science+Business Media.CrossRefGoogle Scholar
Hartman, TE (1965) Density of thin evaporated aluminum films. J Vac Sci Technol 2(5), 239.CrossRefGoogle Scholar
Hutchins, GA (1966) Thickness determination of thin films by electron probe microanalysis. In The Electron Microprobe, McKinley TD, Heinrich KFJ and Wittry DB (Eds.), pp. 390–404. New York: John Wiley and Sons Inc.Google Scholar
Jurek, K, Renner, O and Krouský, E (1994) The role of coating densities in X-ray microanalysis. Mikrochim Acta 114–115(1), 323–326.CrossRefGoogle Scholar
Kerrick, DM, Eminhizer, LB and Villaume, JF (1973) The role of carbon film thickness in electron microprobe analysis. Am Mineral 58, 920–925.Google Scholar
Leder, LB and Suddeth, JA (1960) Characteristic energy losses of electrons in carbon. J Appl Phys 31(8), 1422–1426.CrossRefGoogle Scholar
Limandri, SP, Carreras, AC and Trincavelli, JC (2010) Effects of the carbon coating and the surface oxide layer in electron probe microanalysis. Microsc Microanal 16(5), 583–593.CrossRefGoogle ScholarPubMed
Llovet, X and Salvat, F (2016) PENEPMA: a Monte Carlo programme for the simulation of X-ray emission in EPMA. In IOP Conference Series: Materials Science and Engineering, vol. 109, p. 12009.CrossRefGoogle Scholar
Love, G, Cox, MGC and Scott, VD (1974) Electron probe microanalysis using oxygen x-rays: II. Absorption correction models. J Phys D Appl Phys 7, 2142–2155.CrossRefGoogle Scholar
Lovell, S and Rollinson, E (1968) Density of thin films of vacuum evaporated metals. Nature 218(5147), 1179–1180.CrossRefGoogle Scholar
Pouchou, J-L and Pichoir, F (1990) Surface film X-ray microanalysis. Scanning 12(4), 212–224.CrossRefGoogle Scholar
Ritchie, NWM, Davis, J and Newbury, DE (2008) DTSA-II: A new tool for simulating and quantifying EDS spectra - Application to difficult overlaps. Microsc Microanal 14(Suppl 2), 1176–1177.CrossRefGoogle Scholar
Salvat, F (2015) PENELOPE-2014. A code system for Monte Carlo simulation of electron and photon transport. Available at http://www.oecd-nea.org/lists/penelope.html (retrieved June 27, 2016).Google Scholar
Statham, PJ (2010) Feasibility of X-ray analysis of multi-layer thin films at a single beam voltage. In IOP Conference Series: Materials Science and Engineering, vol. 7, p. 12027.CrossRefGoogle Scholar
Statham, PJ, Llovet, X and Duncumb, P (2012) Systematic discrepancies in Monte Carlo predictions of k-ratios emitted from thin films on substrates. In IOP Conference Series: Materials Science and Engineering, vol. 32, p. 12024.CrossRefGoogle Scholar
Waldo, RA (1988) An iteration procedure to calculate film compositions and thicknesses in electron-probe microanalysis. In Microbeam Analysis, Newbury DE (Ed.), pp. 310–314. San Francisco, CA: San Francisco Press.Google Scholar
Walker, CT (1999) Electron probe microanalysis of irradiated nuclear fuel: An overview. J Anal At Spectrom 14, 447–454.CrossRefGoogle Scholar
Yakowitz, H (1968) Evaluation of specimen preparation and the use of standards in electron probe microanalysis. In 50 Years of Progress in Metallographic Techniques, pp. 383–408. Philadelphia, PA: American Society for Testing of Materials.CrossRefGoogle Scholar
Yakowitz, H and Newbury, DE (1976) A simple analytical method for thin film analysis with massive pure element standards. In Proceedings of the 9th Annual Scanning Electron Microscope Symposium, vol. 1. Chicago, IL: IITRI, pp. 151–152.Google Scholar