Atomic Spectroscopy in the FIM

1986 ◽  
Vol 44 ◽  
pp. 758-761
Author(s):  
J. J. Hren ◽  
S. D. Walck
Keyword(s):  
Electron Microscope ◽  
Electric Fields ◽  
Atom Probe ◽  
Atomic Spectroscopy ◽  
Single Atom ◽  
Statistical Sampling ◽  
Commercial Instrument ◽  
Available Technology ◽  
High Electric Fields ◽  
Field Ion Microscope

The field ion microscope (FIM) has had the ability to routinely image the surface atoms of metals since Mueller perfected it in 1956. Since 1967, the TOF Atom Probe has had single atom sensitivity in conjunction with the FIM. “Why then hasn't the FIM enjoyed the success of the electron microscope?” The answer is closely related to the evolution of FIM/Atom Probe techniques and the available technology. This paper will review this evolution from Mueller's early discoveries, to the development of a viable commercial instrument. It will touch upon some important contributions of individuals and groups, but will not attempt to be all inclusive. Variations in instrumentation that define the class of problems for which the FIM/AP is uniquely suited and those for which it is not will be described. The influence of high electric fields inherent to the technique on the specimens studied will also be discussed. The specimen geometry as it relates to preparation, statistical sampling and compatibility with the TEM will be examined.

Fim/Iap/Tem Studies of Ion Implanted Nickel Emitters

1984 ◽  
Vol 41 ◽  
Author(s):  
S. D. Walck ◽  
J. J. Hren
Keyword(s):  
Electric Fields ◽  
Depth Profiling ◽  
Atom Probe ◽  
Hydrogen Trapping ◽  
Transmission Electron ◽  
Microscope Imaging ◽  
Important Field ◽  
High Electric Fields ◽  
Field Ion Microscope

AbstractAccurate depth profiling of implanted hydrogen and its isotopes in metals is extremely important. Field ion microscopy and atom-probe techniques provide the most accurate depth profiling analytical method of any available. In addition, they are extremely sensitive to hydrogen. This paper reports our early work on hydrogen trapping at defects in metals using the Field Ion Microscope/Imaging Atom Probe (FIM/IAP). Our results deal primarily with the control experiments required to overcome instrumental difficulties associated with in situ implantation and the influence of a high electric field. Transmission Electron Microscopy (TEM) has been used extensively to independently examine the influence of high electric fields on emitters.

Scanning EM in very high electric fields near field ion/emission specimens

1995 ◽  
Vol 53 ◽  
pp. 624-625
Author(s):  
David J. Larson ◽  
Patrick P. Camus ◽  
Thomas F. Kelly
Keyword(s):  
Electron Microscope ◽  
Field Emission ◽  
Electric Fields ◽  
Near Field ◽  
Atom Probe ◽  
Emission Source ◽  
Probe Field ◽  
High Electric Fields ◽  
Scanning Em ◽  
Ion Emission

An atom probe field ion microscope (APFIM) has been constructed inside a NORAN Instruments Automated Digital Electron Microscope (ADEM). The ADEM is a scanning electron microscope (SEM) with a field emission source and a very large vacuum chamber. The APFIM has positive and negative high voltage capability and uses a microchannel-plate/phosphor screen assembly as an imaging and single-ion detector. The APFIM specimen can be cooled by a cryogenic refrigerator. The motivation for this study was the need to deliver an electron beam to the apex of an APFIM specimen while a high field is applied. The beam will be used to thermally pulse the field evaporation rate. The expected field-induced image shift and distortion has been studied previously in a transmission EM with a liquid metal field emission source as a specimen.Fig. 1 shows the interior of the instrument. Computer simulations were done for electron trajectories with negative and positive voltages applied to the emitter based on a simple paraboloidal electric field model described previously.

Field ion microscope investigations of atomic processes at surfaces

1989 ◽  
Vol 47 ◽  
pp. 228-229
Author(s):  
G. L. Kellogg ◽  
P. R. Schwoebel
Keyword(s):  
Single Crystal ◽  
Crystal Surface ◽  
Linear Chain ◽  
Atom Probe ◽  
Nucleation And Growth ◽  
Single Atom ◽  
Initial Structure ◽  
Atomic Processes ◽  
Single Crystal Surfaces ◽  
Field Ion Microscope

Although no longer unique in its ability to resolve individual single atoms on surfaces, the field ion microscope remains a powerful tool for the quantitative characterization of atomic processes on single-crystal surfaces. Investigations of single-atom surface diffusion, adatom-adatom interactions, surface reconstructions, cluster nucleation and growth, and a variety of surface chemical reactions have provided new insights to the atomic nature of surfaces. Moreover, the ability to determine the chemical identity of selected atoms seen in the field ion microscope image by atom-probe mass spectroscopy has increased or even changed our understanding of solid-state-reaction processes such as ordering, clustering, precipitation and segregation in alloys. This presentation focuses on the operational principles of the field-ion microscope and atom-probe mass spectrometer and some very recent applications of the field ion microscope to the nucleation and growth of metal clusters on metal surfaces.The structure assumed by clusters of atoms on a single-crystal surface yields fundamental information on the adatom-adatom interactions important in crystal growth. It was discovered in previous investigations with the field ion microscope that, contrary to intuition, the initial structure of clusters of Pt, Pd, Ir and Ni atoms on W(110) is a linear chain oriented in the <111> direction of the substrate.

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

2019 ◽  
Vol 25 (2) ◽  
pp. 274-279
Author(s):  
John A. Panitz
Keyword(s):  
Field Emission ◽  
National Science Foundation ◽  
Atom Probe ◽  
Single Atom ◽  
National Bureau ◽  
State University ◽  
Pennsylvania State University ◽  
Probe Field ◽  
National Science ◽  
Field Ion Microscope

AbstractThe atom-probe field ion microscope was introduced in 1967 at the 14th Field Emission Symposium held at the National Bureau of Standards (now, NIST) in Gaithersburg, Maryland. 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”. The development of the atom-probe is a story of an instrument that one National Science Foundation (NSF) reviewer called “impossible because single atoms could not be detected”. It is also a story of my life with Erwin Wilhelm Müller as his graduate student in the Field Emission Laboratory at the Pennsylvania State University in the late 1960s and his strong and volatile personality, perhaps fostered by his pedigree as Gustav Hertz’s student in the Berlin of the 1930s. It is the story that has defined by scientific career.

scholarly journals Spatial Resolution in the Atom Probe Field Ion Microscope

1997 ◽  
Vol 3 (S2) ◽  
pp. 1189-1190
Author(s):  
M. K. Miller
Keyword(s):  
Spatial Resolution ◽  
Atom Probe ◽  
Single Atom ◽  
Field Evaporation ◽  
Sensitive Detector ◽  
Probe Field ◽  
3 Dimensional ◽  
Number Of Factors ◽  
The Individual ◽  
Field Ion Microscope

The atom probe field ion microscope can resolve and identify individual atoms. This ability is demonstrated in a pair of field ion micrographs of an Ni3Al specimen, Fig. 1, in which the individual atoms on the close packed (111) plane are clearly resolved. Comparison of these two micrographs reveals that an individual atom was field evaporated between the micrographs. Due to the hemispherical nature of the specimen, the ability to resolve this two dimensional atomic arrangement is only possible on low index plane facets. The spatial resolution in field ion images is determined by a number of factors including specimen temperature, material, microstructural features, specimen geometry, and crystallographic location.The spatial resolution of the data obtained in atom probe and 3 dimensional atom probe compositional analyses can be evaluated with the use of field evaporation or field desorption images. The field evaporation images are formed from the surface atoms with the use of a single atom sensitive detector whereas the field ion image is formed from the projection of a continuous supply of ionized image gas atoms.

Applications of Atom Probe Microanalysis in Materials Science

MRS Bulletin ◽  
1994 ◽  
Vol 19 (7) ◽  
pp. 27-34 ◽  
Author(s):  
M.K. Miller ◽  
G.D.W. Smith
Keyword(s):  
Grain Boundaries ◽  
Materials Science ◽  
Direct Method ◽  
Light Element ◽  
Atom Probe ◽  
Single Atom ◽  
Probe Field ◽  
Probe Technique ◽  
Wide Range ◽  
Field Ion Microscope

The atom probe field ion microscope is the most powerful and direct method for the analysis of materials at the atomic level. Since analyses are performed by collecting atoms one at a time from a small volume, it is possible to conduct fundamental characterization of materials at this level. The atom probe technique is applicable to a wide range of materials since its only restriction is that the material under analysis must possess at least some limited electrical conductance. Therefore, since its introduction in 1968, the atom probe field ion microscope has been used in many diverse applications in most branches of materials science. Many of the applications have exploited its high spatial resolution capabilities to perform microstructural characterizations of features such as grain boundaries and other interfaces and ultrafine scale precipitation that are not possible with other microanaly tical techniques. This article briefly outlines some of the capabilities and applications of the atom probe. The details of the atom probe technique are described elsewhere.The power of the atom probe may be demonstrated by its ability to see and identify a single atom, which is particularly useful in characterizing solute segregation to grain boundaries or other interfaces. An example of a brightly-imaging solute atom at a grain boundary in a nickel aluminide is shown in Figure 1. In order to conclusively determine its identity, its image is aligned with the probe aperture in the center of the imaging screen and then the selected atom is carefully removed by field evaporation and analyzed in the time-of-flight mass spectrometer. This and many other bright spots in this material were shown to be boron atoms. This example also illustrates the light element analytical capability of the atom probe. In fact, the atom probe may to used to analyze all elements in the periodic table and has had applications ranging from characterizing the distribution of implanted hydrogen to phase transformations in uranium alloys.

Prospects for atom-probe analysis in biology and medicine

1994 ◽  
Vol 52 ◽  
pp. 824-825 ◽  
Author(s):  
J. A. Panitz
Keyword(s):  
Electric Fields ◽  
Biological Samples ◽  
Depth Resolution ◽  
Atom Probe ◽  
Atomic Resolution ◽  
Charge Ratio ◽  
Single Atom ◽  
Probe Field ◽  
Probe Analysis ◽  
Atom Probe Analysis

The atom-probe field ion microscope may be the ultimate microanalytical tool because a single atom, chosen from its neighbors at the discretion of the experimenter, can be visualized in atomic resolution and then identified by its mass-to-charge ratio. Although the analysis procedure is destructive;the lateral and depth resolution of the atom-probe is impressive, exceeding 0.5 nm under favorable conditions. Despite these attributes, atom probe analysis has been largely confined to problems in the materials sciences. The atom probe has made no impact in biology or medicine, largely because of restrictions imposed by the technique on the preparation, imaging, and analysis of biological samples. Recent developments in each of these areas has made atom probe analysis of biological samples a more viable prospect.Biological Sample PreparationThe atom-probe technique places severe restrictions on the type of sample that can be analyzed. Field ionization is used to image a surface in atomic resolution, and field desorption provides a source of ions for analysis. These processes occur with a high probability only in electric fields greaterthan 100 MV/cm. Electric fields of this magnitude (and the nature of the imaging process) require theuse of a needlelike substrate, known as a field-emitter "tip".

Advances of Field Ion Microscopy by the Atom-Probe Fim

1970 ◽  
Vol 28 ◽  
pp. 530-531
Author(s):  
Erwin W. Müller
Keyword(s):  
Point Defects ◽  
Unique Feature ◽  
Atom Probe ◽  
Single Atom ◽  
Physical Metallurgy ◽  
Field Evaporation ◽  
Bulk Structure ◽  
Field Ion Microscope ◽  
Atom Layer

Since its conception 15 years ago the field ion microscope has remained the only device capable of imaging a specimen in atomic detail. The unique feature of seeing point defects, dislocation cores and the atomic structure of grain boundaries and precipitates made the instrument a useful tool of physical metallurgy, particularly since various in-situ treatments and the capability of dissecting the specimen atom layer by atom layer with the help of controlled field evaporation made the bulk structure accessible. As different atoms look very much alike, a way of identifying them was needed. The most unambiguous identification, by mass spectrometry, has now been obtained with the atom-probe FIM. A single atom, as seen in the million times magnified image, can be chosen by the microscopist, picked up and sent through a mass spectrometer.

Molecular Imaging in High Electric Fields

1981 ◽  
Vol 39 ◽  
pp. 18-21
Author(s):  
J. A. Panitz
Keyword(s):  
Electric Fields ◽  
Organic Molecules ◽  
Copper Phthalocyanine ◽  
Image Resolution ◽  
Monomolecular Films ◽  
Electron Lens ◽  
High Electric Fields ◽  
Point Projection ◽  
Field Ion Microscope ◽  
Clean Metal

For the past thirty years, attempts have been made to use the field-electron emission microscope (FEEM), and the field-ion microscope (FIM) to image organic molecules. These attempts were inspired by the simplicity of the techniques and the potential for achieving high image contrast, magnification, and resolution. Since both microscopies rely on direct point projection for imaging, there is no need for electron-lens systems or devices to minimize specimen vibration. As a result, both techniques offer the hope of achieving high quality molecular images with a minimum of effort.In the early 1950's the FEEM was the only microscope which had demonstrated a magnification of 106 at an image resolution better than 2nm. Since it had already been used to image the diffusion of monomolecular films on clean metal surfaces, there was growing optimism that individual organic molecules could be imaged as well. In 1951, striking FEEM patterns of flaventhrene and copper-phthalocyanine were obtained which displayed the known symmetry of each molecule (two-fold and four-fold, respectively). Unfortunately, the success of these experiments was relatively shortlived.

Anecdotes from an Atom-Probe Original

1998 ◽  
Vol 4 (S2) ◽  
pp. 74-75 ◽  
Author(s):  
J. A. Panitz
Keyword(s):  
Graduate Students ◽  
Field Emission ◽  
Metal Surface ◽  
Atom Probe ◽  
Single Atom ◽  
Probe Field ◽  
Single Atoms ◽  
Penn State ◽  
Field Ion Microscope

The Atom-Probe Field Ion Microscope was introduced in 1967 at the 14th Field Emission Symposium in Gaithersburg, Maryland. The Atom-Probe 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”. The development of the Atom-Probe is a story that highlights Erwin Muller's strong and sometimes volatile personality. It is a story of an instrument that one NSF proposal reviewer called “impossible” because “single atoms could not be detected”. It is also the story of the Field Emission Laboratory at Penn State in the late 1960s and the contributions of two superb technicians, Gerald Fowler and Brooks McLane, and two graduate students, Douglas Barofsky and John Panitz. The anecdotes from this time are colorful and reflect Erwin's pedigree as Gustav Hertz's student in the Berlin of the 1930s.

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