High-flux monochromatic ion and electron beams based on laser-cooled atoms

Kime, L.; Fioretti, A.; Bruneau, Yoann; Porfido, N.; Fuso, Francesco; Viteau, Matthieu; Khalili, Guyve; Šantić, Neven; Gloter, Alexandre; Rasser, B.; Sudraud, P.; Pillet, P.; Comparat, D.

doi:10.1103/physreva.88.033424

Cited by 45 publications

(60 citation statements)

References 99 publications

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“…Cooling and compressing atoms originating from a thermal source (such as a Knudsen cell) allows for the creation of beams with equal brightness but even higher currents since the availability of the very large flux from such a source allows the selection of the best part of the laser cooled atom beam and thus keeping high brightness up to currents of the target 1 nA. The FIB source considered here, as the one of Kime et al [15], therefore uses a Knudsen cell as atomic source. In our case, the Knudsen cell is connected to a heated collimation tube [16,17] which increases the lifetime of the atomic reservoir by more than an order of magnitude and alters the velocity distribution such that even more atoms can be captured in the magneto-optical compressor (MOC).…”

Section: Introductionmentioning

confidence: 99%

Performance predictions for a laser-intensified thermal beam for use in high-resolution focused-ion-beam instruments

et al. 2014

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Photo-ionization of a laser-cooled and compressed atomic beam from a high-flux thermal source can be used to create a high-brightness ion beam for use in Focus Ion Beam (FIB) instruments. Here we show using calculations and Doppler cooling simulations that an atomic rubidium beam with a brightness of 2.1 × 10 7 A/(m 2 sr eV) at a current of 1 nA can be created using a compact 5 cm long 2D magneto-optical compressor which is more than an order of magnitude better than the current state of the art Liquid Metal Ion Source.

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Section: Introductionmentioning

confidence: 99%

Performance predictions for a laser-intensified thermal beam for use in high-resolution focused-ion-beam instruments

et al. 2014

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“…[20]. Briefly, it consists of a recirculating Cs oven outsourcing an effusive flux of cesium atoms, a laser-cooling region, an atomic excitation/ionization region, and finally a FIB column.…”

Section: Methodsmentioning

confidence: 99%

“…The system represents the practical implementation of our original proposal [20]. Atomic ionization is obtained either by laser promoting the neutral atoms into highly excited Rydberg states that are subsequently field-ionized, or by direct laser photoionization.…”

Section: Introductionmentioning

confidence: 99%

Ion microscopy based on laser-cooled cesium atoms

Viteau¹,

Reveillard²,

Kime³

et al. 2016

Ultramicroscopy

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We demonstrate a prototype of a Focused Ion Beam machine based on the ionization of a lasercooled cesium beam adapted for imaging and modifying different surfaces in the few-tens nanometer range. Efficient atomic ionization is obtained by laser promoting ground-state atoms into a target excited Rydberg state, then field-ionizing them in an electric field gradient. The method allows obtaining ion currents up to 130 pA. Comparison with the standard direct photo-ionization of the atomic beam shows, in our conditions, a 40-times larger ion yield. Preliminary imaging results at ion energies in the 1-5 keV range are obtained with a resolution around 40 nm, in the present version of the prototype. Our ion beam is expected to be extremely monochromatic, with an energy spread of the order of 1 eV, offering great prospects for lithography, imaging and surface analysis.

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“…Alternatively, one can excite the atoms to a Rydberg state and ionize the atoms by means of field ionization. 18 The current I in the ion beam is set by varying the radius r i of the selection aperture, which is given by…”

Section: Source Designmentioning

confidence: 99%

Performance predictions of a focused ion beam from a laser cooled and compressed atomic beam

Haaf

Wouters

Geer

et al. 2014

Journal of Applied Physics

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Focused ion beams are indispensable tools in the semiconductor industry because of their ability to image and modify structures at the nanometer length scale. Here we report on performance predictions of a new type of focused ion beam based on photo-ionization of a laser cooled and compressed atomic beam. Particle tracing simulations are performed to investigate the effects of disorder-induced heating after ionization in a large electric field. They lead to a constraint on this electric field strength which is used as input for an analytical model which predicts the minimum attainable spot size as a function of amongst others the flux density of the atomic beam, the temperature of this beam and the total current. At low currents (I < 10 pA) the spot size will be limited by a combination of spherical aberration and brightness, while at higher currents this is a combination of chromatic aberration and brightness. It is expected that a nanometer size spot is possible at a current of 1 pA. The analytical model was verified with particle tracing simulations of a complete focused ion beam setup. A genetic algorithm was used to find the optimum acceleration electric field as a function of the current. At low currents the result agrees well with the analytical model while at higher currents the spot sizes found are even lower due to effects that are not taken into account in the analytical model.

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High-flux monochromatic ion and electron beams based on laser-cooled atoms

Cited by 45 publications

References 99 publications

Performance predictions for a laser-intensified thermal beam for use in high-resolution focused-ion-beam instruments

Performance predictions for a laser-intensified thermal beam for use in high-resolution focused-ion-beam instruments

Ion microscopy based on laser-cooled cesium atoms

Performance predictions of a focused ion beam from a laser cooled and compressed atomic beam

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