Reflections on the Projection of Ions in APT 245


Figure 8. Effect of the projection model on the reconstruction of a thin layer normal to the direction of analysis for a simulated geometry of R=90nm and α=14°. The ideally reconstructed layer is depicted as dashed black lines. The equidistant projection model (blue) gives satisfactory results, whereas pseudo-stereographic model needs adjustment of the parameters with respect to the physical parameters. ICF, image compression factor.


CONCLUSIONS


In conclusion, we would like to point that the pseudo- stereographic projection was introduced in the early imple- mentation of the tomographic reconstruction protocol, and, for the small field-of-view instruments, was working fine. Although it has been extended to wide angle instruments, it should in fact only be considered as a small-angle approxi- mation of the real projections. The azimuthal equidistant model, although not ideal, has a validity domainmuch closer to the modern instruments setup. In summary, we have shown that


∙ the ion projection in APT and FIM is best described by an azimuthal equidistant projection;


∙ the azimuthal equidistant is expected to work on a broad range of specimen geometries;


∙ this projection was shown to be not only more accurate, but also more robust than the pseudo-stereographic projection when it comes to errors on, e.g., the position of the center of the projection;


∙ the implementation of a protocol based on such a projection is simple and could easily be generalized.


ACKNOWLEDGMENT


Dr. M.P. Moody, Dr. L.T. Stephenson, Dr. R.K.W. Marceau, Dr.D.Haley,Dr.T.C. Peterson,Dr. F.Vurpillot,Dr.B.P.Geiser, and Dr. D.J. Larson are all thanked for fruitful discussions over the years. The authors extend their gratitude to Shyeh Tjing Cleo Loi who developed and performed the Lorentz-based simula- tions that have enabled part of this work. B.G. is grateful for the support from Prof. S.P. Ringer and Prof. J.M. Cairney as well as the Australian Microscopy & Microanalysis Research Facility at the University of Sydney, where some of the data presented herein was obtained. Dr. Eric Jägle and Liang Wu are acknowledged for the provision of the pure Al data set obtained


on the Cameca LEAP 5000. For the record, the authors owe Dr. Jägle an alcoholic beverage to thank him for letting the authors use the data set. Finally, B.G. is grateful for the support provided by Prof. Raabe and the group atMPIE.


REFERENCES


BAS, P., BOSTEL, A.,DECONIHOUT,B.&BLAVETTE,D. (1995). A general protocol for the reconstruction of 3D atom probe data. Appl Surf Sci 87/88, 298–304.


BLAVETTE, D., SARRAU, J.M., BOSTEL,A.&GALLOT, J. (1982). Direction and depth of atom probe analysis. Rev De Phys Appl 17(7), 435–440.


BRANDON, D.G. (1964). Accurate determination of crystal orientation from field ion micrographs. J Sci Instrum 41(6), 373–375.


BRITTON, T.B., JIANG, J., GUO, Y., VILALTA-CLEMENTE, A., WALLIS, D., HANSEN, L.N., WINKELMANN,A.&WILKINSON, A.J. (2016). Tutorial: Crystal orientations and EBSD or which way is up? Mater Charact 117, 113–126.


CEREZO, A.,WARREN,P. & SMITH, G. (1999). Some aspects of image projection in the field-ion microscope. Ultramicroscopy 79(1–4), 251–257.


GAULT,B., HALEY,D., DE GEUSER, F., MOODY,M.P., MARQUIS,E.A., LARSON,D.J.&GEISER, B.P. (2011). Advances in the reconstruction of atom probe tomography data. Ultramicroscopy 111(6), 448–457.


GAULT, B.,MOODY, M.P.,DEGEUSER, F., TSAFNAT, G., LA FONTAINE, A., STEPHENSON, L.T., HALEY,D.&RINGER, S.P. (2009). Advances in the calibration of atom probe tomographic reconstruction. J Appl Phys 105, 034913.


GEISER, B.P., LARSON, D.J., OLTMAN, E., GERSTL, S.S., REINHARD, D.A., KELLY, T.F. & PROSA, T.J. (2009). Wide-field-of-view atom probe reconstruction. Microsc Microanal 15(Suppl 2), 292–293.


GIPSON, G.S. (1980). An improved empirical-formula for the electric-field near the surface of field emitters. J Appl Phys 51(7), 3884–3889.


HYDE, J.M., CEREZO, A., SETNA, R.P., WARREN, P.J. & SMITH, G.D.W. (1994). Lateral and depth scale calibration of the position sensitive atom probe. Appl Surf Sci 76/77, 382–391.


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50  |  Page 51  |  Page 52  |  Page 53  |  Page 54  |  Page 55  |  Page 56  |  Page 57  |  Page 58  |  Page 59  |  Page 60  |  Page 61  |  Page 62  |  Page 63  |  Page 64  |  Page 65  |  Page 66  |  Page 67  |  Page 68  |  Page 69  |  Page 70  |  Page 71  |  Page 72  |  Page 73  |  Page 74  |  Page 75  |  Page 76  |  Page 77  |  Page 78  |  Page 79  |  Page 80  |  Page 81  |  Page 82  |  Page 83  |  Page 84  |  Page 85  |  Page 86  |  Page 87  |  Page 88  |  Page 89  |  Page 90  |  Page 91  |  Page 92  |  Page 93  |  Page 94  |  Page 95  |  Page 96  |  Page 97  |  Page 98  |  Page 99  |  Page 100  |  Page 101  |  Page 102  |  Page 103  |  Page 104  |  Page 105  |  Page 106  |  Page 107  |  Page 108  |  Page 109  |  Page 110  |  Page 111  |  Page 112  |  Page 113  |  Page 114  |  Page 115  |  Page 116  |  Page 117  |  Page 118  |  Page 119  |  Page 120  |  Page 121  |  Page 122  |  Page 123  |  Page 124  |  Page 125  |  Page 126  |  Page 127  |  Page 128  |  Page 129  |  Page 130  |  Page 131  |  Page 132  |  Page 133  |  Page 134  |  Page 135  |  Page 136  |  Page 137  |  Page 138  |  Page 139  |  Page 140  |  Page 141  |  Page 142  |  Page 143  |  Page 144  |  Page 145  |  Page 146  |  Page 147  |  Page 148  |  Page 149  |  Page 150  |  Page 151  |  Page 152  |  Page 153  |  Page 154  |  Page 155  |  Page 156  |  Page 157  |  Page 158  |  Page 159  |  Page 160  |  Page 161  |  Page 162  |  Page 163  |  Page 164  |  Page 165  |  Page 166  |  Page 167  |  Page 168  |  Page 169  |  Page 170  |  Page 171  |  Page 172  |  Page 173  |  Page 174  |  Page 175  |  Page 176  |  Page 177  |  Page 178  |  Page 179  |  Page 180  |  Page 181  |  Page 182  |  Page 183  |  Page 184  |  Page 185  |  Page 186  |  Page 187  |  Page 188  |  Page 189  |  Page 190  |  Page 191  |  Page 192  |  Page 193  |  Page 194  |  Page 195  |  Page 196  |  Page 197  |  Page 198  |  Page 199  |  Page 200  |  Page 201  |  Page 202  |  Page 203  |  Page 204  |  Page 205  |  Page 206  |  Page 207  |  Page 208  |  Page 209  |  Page 210  |  Page 211  |  Page 212  |  Page 213  |  Page 214  |  Page 215  |  Page 216  |  Page 217  |  Page 218  |  Page 219  |  Page 220  |  Page 221  |  Page 222  |  Page 223  |  Page 224  |  Page 225  |  Page 226  |  Page 227  |  Page 228  |  Page 229  |  Page 230  |  Page 231  |  Page 232  |  Page 233  |  Page 234  |  Page 235  |  Page 236  |  Page 237  |  Page 238  |  Page 239  |  Page 240  |  Page 241  |  Page 242  |  Page 243  |  Page 244  |  Page 245  |  Page 246  |  Page 247  |  Page 248  |  Page 249  |  Page 250  |  Page 251  |  Page 252  |  Page 253  |  Page 254  |  Page 255  |  Page 256  |  Page 257  |  Page 258  |  Page 259  |  Page 260  |  Page 261  |  Page 262  |  Page 263  |  Page 264  |  Page 265  |  Page 266  |  Page 267  |  Page 268  |  Page 269  |  Page 270  |  Page 271  |  Page 272  |  Page 273  |  Page 274  |  Page 275  |  Page 276  |  Page 277  |  Page 278  |  Page 279  |  Page 280  |  Page 281  |  Page 282  |  Page 283  |  Page 284