Cameca

Centre National De La Recherche Scientifique

Cnrs

Alain Bostel

Bernard Deconihout

François Vurpillot

Mikhail Yavor

Ludovic Renaud

Didier Blavette

Mikaïl Yavor

A tomographic atom probe uses electrical pulses applied to an electrode in order to carry out evaporation of the sample being analyzed. In order to produce these electrical pulses, the tomographic atom probe comprises a high-voltage generator connected to an electrode by an electrical connection comprising a chip of semiconductor material. The probe also comprises a light source which can be controlled in order to generate light pulses which are applied to the semiconductor chip. Throughout the illumination, the chip is rendered conductive, which puts the high-voltage generator and the electrode in electrical contact so that a potential step is applied to the latter. The probe also comprises means for applying a voltage step of opposite amplitude to the previous step at the end of a time interval &#x394;t, so that the electrode finally receives a voltage pulse of duration &#x394;t.

Tomographic atom probe comprising an electro-optical generator of high-voltage electrical pulses

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.

High resolution wide angle tomographic probe

Transparent position-sensitive particle detector

Growing community of inventors

Le Petit Quevilly, France

Alain Bostel