SINGLE ATOM DETECTABILITY OF A ToF ATOM-PROBE

1984 ◽  
Vol 45 (C9) ◽  
pp. C9-343-C9-347 ◽  
Author(s):  
T. Sakurai ◽  
T. Hashizume ◽  
A. Jimbo
Keyword(s):  
Atom Probe ◽  
Single Atom

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.

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.

Three-dimensional reconstruction of atomic-scale composition with the position-sensitive atom probe

1992 ◽  
Vol 50 (2) ◽  
pp. 1478-1479
Author(s):  
G.D.W. Smith ◽  
A. Cerezo ◽  
C.R.M. Grovenor ◽  
T.J. Godfrey ◽  
R.P. Setna
Keyword(s):  
Mass Spectrometer ◽  
Three Dimensional ◽  
Atom Probe ◽  
Atomic Scale ◽  
Single Atom ◽  
Small Aperture ◽  
Dimensional Reconstruction ◽  
Position Sensitive ◽  
Atom Level ◽  
Scale Composition

The combination of a field ion microscope with a time-of-flight mass spectrometer provides the capability for chemical microanalysis at the single atom level. Such an instrument is termed an Atom Probe. Conventionally, the connection between the microscope and the mass spectrometer is made via a small aperture hole in the imaging screen. This defines a region on the specimen, typically about 2nm across, from which the analysis is obtained. The disadvantage of this arrangement is that other regions of the specimen cannot be examined, as ions from all but the selected area strike the image screen and therefore do not pass into the mass spectrometer. In order to overcome this problem, we have developed a version of the Atom Probe which incorporates a wide-angle position sensitive detector system. This instrument, which we have termed the POSAP, is shown schematically in figure 1. Typically, the field of view in this instrument is about 20nm across. The number of ions collected per atom layer removed from the specimen surface is therefore approximately 5,000.

Impact of Carbon on Threshold Voltage Shift in MOSFET Studied by 3D Atom Probe Tomography

2017 ◽  
Author(s):  
Ju-Heon Kim ◽  
Euna Ok ◽  
Hyunmi Sim ◽  
Dongkeun Na ◽  
Ho Seok Song ◽  
...  
Keyword(s):  
Threshold Voltage ◽  
Atom Probe Tomography ◽  
Analytical Techniques ◽  
Gate Oxide ◽  
Atom Probe ◽  
Single Atom ◽  
Device Performance ◽  
Si Substrate ◽  
Threshold Voltage Shift ◽  
Voltage Shift

Abstract In this paper, impact of carbon on threshold voltage in MOSFET-based device is studied by 3D-atom probe tomography (APT). Carbon is one of most difficult contaminants incorporated from fab-environment to be detected by typical analytical techniques such as TEM-EDS or SIMS. Here, we successfully demonstrated the detection of carbon segregated at gate oxide/Si substrate interface using 3D-APT with single-atom sensitivity and sub-nanometer spatial resolution. It was found that the carbon contaminants have significant effect on the threshold voltage shift (ΔVth), in which ΔVth increases slightly with increasing carbon concentration. The deterioration of device performance is explained by means of which the positively ionized carbons at the interface acting as additional positive charges affecting the inversion to n-channel.

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.

Recent developments in position-sensitive atom-probe microanalysis

1994 ◽  
Vol 52 ◽  
pp. 828-829
Author(s):  
G. D. W. Smith ◽  
A. Cerezo ◽  
T. J. Godfrey ◽  
R. Setna ◽  
J. M. Hyde ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Atom Probe ◽  
Atomic Scale ◽  
Three Dimensions ◽  
Single Atom ◽  
Position Sensing ◽  
Recent Developments ◽  
Position Sensitive ◽  
New Generation ◽  
Serial Mode

The difficulties associated with the aperture geometry of the conventional atom probe have been overcome by the introduction of a new generation of wide-angle, single-atom sensitivity, positionsensitive detectors. With the aid of such detectors, it is now possible to map the locations and identitiesof atoms over regions of solid surface up to 50 nm in diameter. The nanometer-scale chemistry of successive atomic layers can be investigated during the process of field evaporation. We therefore have the new and exciting ability to investigate the atomic-scale chemistry of solids in three dimensions. The first three-dimensional atom probe is the PoSAP (Position Sensitive Atom Probe), developed at Oxford by Cerezo and Smith. In this instrument, position sensing is carried out by means of a wedge-and-strip anode assembly, located directly behind the double microchannel plate used for primary ion detection and time of flight measurement. The detector readout functions in serial mode. Only one ioncan be successfully detected and identified for each evaporation pulse which is applied to the specimen

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".

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