Cameca

Mikhail Yavor

Alain Bostel

Bernard Deconihout

Ludovic Renaud

A mass analysis device with wide angular acceptance, notably of the mass spectrometer or atom probe microscope type, includes means for receiving a sample, means for extracting ions from the surface of the sample, and a reflectron producing a torroidal electrostatic field whose equipotential lines are defined by a first curvature in a first direction and a first center of curvature, and a second curvature in a second direction perpendicular to the first direction and a second center of curvature, the sample being positioned close to the first center of curvature.

Mass analysis device with wide angular acceptance including a reflectron

The present invention concerns the enhancing of the mass resolution of wide angle tomographic atom probes. The invention consists of an atom probe also comprising a sample-holding device and a detector which are separated from one another by a distance L and enclosed in a chamber, an 'Einzel' type electrostatic lens consisting of three electrodes arranged inside the chamber between the sample and the detector, to which electrical potentials are applied so as to form an electrical field that strongly focuses the beam of ions emitted by the sample under test when the probe is operating. According to the invention, the geometry of the electrodes is defined precisely so as to greatly limit the effects of the spherical aberration that affects the 'Einzel' lens on the beam of ions, said spherical aberration being clearly sensitive when the lens is greatly polarized. The invention applies more particularly to the atom probes known as 3D atom probes.

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Saint-Petersburg, Russia

Mikhail Yavor