The Atom-Probe Field Ion Microscope

Abstract

A serious limitation of the field ion microscope has been its inability to identify the chemical nature of the individually imaged atoms. The newly conceived atom-probe FIM is a combination probe-hole FIM and mass spectrometer having single particle sensitivity. During observation, the observer selects an atomic site of interest by placing it over a probe hole in the image screen. Pulsed field evaporation sends the chosen particle through the hole and into the spectrometer section. Preliminary results show that field evaporation of tungsten under poor vacuum conditions occurs as triply or quadruply charged WO, WN, WO2, and WN2 ions, while under better conditions doubly and possibly triply charged tungsten can be observed. Mo–Re alloys always produced doubly charged molybdenum and rhenium ions when examined in the atom-probe. Wide applications for the study of short range order in alloys, the chemical nature of precipitates and impurity atoms, and information regarding the imaging properties of various atom species, of both the substrate and adsorbed material, are foreseen.

Atom probe tomography

“…Müller and Panitz,16 in 1967, and Müller et al, 17 in 1968, introduced the atom probe field ion microscope ͑APFIM͒. The atom probe is a combination of a field ion microscope and a mass spectrometer, as shown in Fig.…”

EELS quantification near the single-atom detection level

“…The ability of EELS to analyze a single atom while leaving it in its surroundings distinguishes it from other techniques such as time-of-flight field-ion spectroscopy (atom-probe), which has been able to detect and analyze single atoms for some time [19], but only once they have been desorbed from a sharp tip. It also gives a marked advantage to EELS over scanning tunneling spectroscopy, which has no element-specific signal with which to work.…”

My Life with Erwin: The Beginning of an Atom-Probe Legacy

“…The Atom-Probe Field Ion Microscope was; and remains, the only instrument capable of determining "the nature of one single atom seen on a metal surface and selected from neighboring atoms at the discretion of the observer" [2]. The development of the Atom-Probe is a story of an instrument that one NSF reviewer called "impossible because single atoms could not be detected".…”