New Atom Probe Tomography Reconstruction Algorithm for Multilayered Samples 253
algorithms, the new one provides a more accurate analyzed depth and improves the spatial resolution close to the inter- face. New reconstructions are qualitatively similar to that obtained by the previous simulation based approach proposed to take into account the nonhemispherical specimen mor- phology. But the currentwork is not limited by computational resource constraints and the reconstruction algorithm was successfully applied on experimental data.
ACKNOWLEDGMENTS
The authors acknowledge the support of the French Agence Nationale de la Recherche (ANR) under reference ANR-12- NANO-0001. The authors acknowledge the University of California, Santa Barbara for providing the samples.
REFERENCES
BAS, P., BOSTEL, A.,DECONIHOUT,B.&BLAVETTE,D. (1995). A general protocol for the reconstruction of 3D atom probe data. Appl Surf Sci 87, 298–304.
BEINKE, D., OBERDORFER,C.&SCHMITZ, G. (2016). Towards an accurate volume reconstruction in atom probe tomography. Ultramicroscopy 165,34–41.
BLAVETTE, D., SARRAU, J.M., BOSTEL,A.&GALLOT, J. (1982). Direction et distance d’analyse à la sonde atomique. Revue de Physique Appliquée 17, 435–440.
Figure 6. a: Applied voltage curve during the analyses of a sam- ple made up of a 35 nm InAlN layer embedded between two GaN layers. A fit of the voltage curve first part indicates that the field ratio between GaN and InAlN is around 1.38. b: Voltage curve new reconstruction. c: Standard voltage curve reconstruction.
the widths of the other layers would be overestimated. The underpinning conclusion is that conventional algorithms cannot provide accurate width measurements for more than one layer. On the contrary, the flexibility of the new algo- rithm emerging from the introduction of new degrees of freedom (interfaces positions and field ratios) is a real asset to provide accurate measurements.
CONCLUSION
A new algorithm dedicated to the 3D reconstruction of multilayered sampleswas
presented.The approach is based on classical relationship between electric field and curvature. But themethod is not constrained by a hemispherical assumption for the specimen shape. This is achieved by considering the mean curvature as a 3D concept, which leads to the intro- duction of a specific class of constant mean curvature surfaces of revolution, namely the Delaunay surfaces. As a result, the radial magnification variations due to presence of different materials are taken into account. Two versions of the new algorithmcorresponding to extensions of standard cone angle
and voltage curve algorithms were introduced. Simulations of field evaporation of bilayer samples were performed in order to evaluate the new method. Compared to conventional
DELAUNAY, C. (1841). Sur la surface de révolution dont la courbure moyenne est constante. Journal de Mathématiques Pures et Appliquées 6, 309–314.
GAULT, B., HALEY, D., DE GEUSER, F., MOODY, M.P., MARQUIS, E.A., LARSON,D.J. & GEISER,B.P.
(2011a). Advances in the
reconstruction of atom probe tomography data. Ultramicroscopy 111,448–457.
GAULT, B., LOI, S.T., ARAULLO-PETERS, V.J., STEPHENSON, L.T., MOODY, M.P., SHRESTHA, S.L., MARCEAU, R.K.W., YAO, L., CAIRNEY, J.M. & RINGER, S.P. (2011b). Dynamic reconstruc- tion for atom probe tomography. Ultramicroscopy 111, 1619–1624.
GEISER, B.P., LARSON, D.J., OLTMAN, E., GERSTL, S., REINHARD, D., KELLY, T.F. & PROSA, T.J. (2009). Wide-field-of-view atom probe reconstruction. Microsc Microanal 15, 292–293.
GOMER, R. (1961). Field Ionization and Field Emission. Cambridge, MA: Harvard, University Press.
HALEY, D., MOODY, M.P. & SMITH, G.D.W. (2013). Level set methods for modelling field evaporation in atom probe. Microsc Microanal 19, 1709–1717.
LARSON,D.J.,GEISER,B.P., PROSA, T.J.,GERSTL, S.S.A., REINHARD,D.A.& KELLY, T.F. (2011). Improvements in planar feature reconstructions in atom probe tomography. JMicrosc 243,15–30.
LARSON, D.J., GEISER,B.P., PROSA,T.J.&KELLY,T.F.(2012).Onthe use of simulated field-evaporated specimen apex shapes in atom probe tomography data reconstruction. Microsc Microanal 18, 953–963.
MARQUIS, E.A., GEISER, B.P., PROSA, T.J. & LARSON, D.J. (2011). Evolution of tip shape during field evaporation of complex multilayer structures. J Microsc 241, 225–233.
OBERDORFER, C., EICH, S.M., LÜTKEMEYER,M. & SCHMITZ, G. (2015). Applications of a versatile modelling approach to 3D atom probe simulations. Ultramicroscopy 159, Part 2, 184–194.
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