MECHANISMS AND ENERGETICS OF SURFACE ATOMIC PROCESSES, AN ATOM-PROBE FIELD ION MICROSCOPE STUDY

The energies involved in various surface atomic processes such as surface diffusion, the binding of small atomic clusters on the surface, the interaction between two adsorbed atoms, the dissociation of an atom from a small cluster or from a surface layer, the binding of kink site atoms or atoms at different adsorption sites to the surface etc., can be derived from an analysis of atomically resolved field ion microscope images and a kinetic energy measurement of low temperature field desorbed ions using the time-of-flight atom-probe field ion microscope. These energies can be used to compare with theories and to understand the transport of atoms on the surface in atomic reconstructions, epitaxial growth of surface layers and crystal growth, adsorption layer superstructure formation, and also why an atomic ordering or atomic reconstruction at the surface is energetically favored. Mechanisms of some of the surface atomic processes are also clarified from these quantitative, atomic resolution studies. Very recent work in this area is briefly reviewed.

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Mechanisms and Energetics of Surface Atomic Processes, an Atom-Probe Field Ion Microscope Study

MRS Proceedings ◽

10.1557/proc-295-49 ◽

1992 ◽

Vol 295 ◽

Author(s):

Tien T. Tsong

Keyword(s):

Dynamical Behavior ◽

Atom Probe ◽

Solid Surfaces ◽

Atomic Scale ◽

High Tech ◽

Composition Analysis ◽

Atomic Processes ◽

Probe Field ◽

Atomic Image ◽

Field Ion Microscope

AbstractAtom-probe field ion microscopy is capable of imaging solid surfaces with atomic resolution, and at the same time chemically analyzing atoms selected by the observer from the atomic image. The samples are restricted to those having a tip shape, but in many cases this is no longer a drawback since structures in high-tech materials are reducing in size to that comparable to or smaller than the field ion emitter tip. This technique is finding many applications in different areas. Our recent applications of this technique to the study of the dynamical behavior of surfaces and surface atoms and their mechanisms and energetics, and the atomic scale chemical and composition analysis will be briefly described.

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Mechanisms and Energetics of Surface Atomic Processes, an Atom-Probe Field ion Microscope Study

MRS Proceedings ◽

10.1557/proc-280-87 ◽

1992 ◽

Vol 280 ◽

Author(s):

Tien T. Tsong

Keyword(s):

Dynamical Behavior ◽

Atom Probe ◽

Solid Surfaces ◽

Atomic Scale ◽

High Tech ◽

Composition Analysis ◽

Atomic Processes ◽

Probe Field ◽

Atomic Image ◽

Field Ion Microscope

ABSTRACTAtom-probe field ion microscopy is capable of imaging solid surfaces with atomic resolution, and at the same time chemically analyzing atoms selected by the observer from the atomic image. The samples are restricted to those having a tip shape, but in many cases this is no longer a drawback since structures in high-tech materials are reducing in size to that comparable to or smaller than the field ion emitter tip. This technique is finding many applications in different areas. Our recent applications of this technique to the study of the dynamical behavior of surfaces and surface atoms and their mechanisms and energetics, and the atomic scale chemical and composition analysis will be briefly described.

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Field ion microscope investigations of atomic processes at surfaces

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100153117 ◽

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.

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Fabrication and characterization - by High Resolution Electron Microscopy and atom probe microanalysis - of Co-based metallic multilayer films

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010017699x ◽

1990 ◽

Vol 48 (4) ◽

pp. 772-773

Author(s):

Amanda K. Petford-Long ◽

A. Cerezo ◽

M.G. Hetherington

Keyword(s):

Electron Microscopy ◽

High Resolution ◽

High Resolution Electron Microscopy ◽

Atom Probe ◽

Multilayer Films ◽

Interface Roughness ◽

Probe Field ◽

Resolution Electron ◽

Potential Applications ◽

Field Ion Microscope

The fabrication of multilayer films (MLF) with layer thicknesses down to one monolayer has led to the development of materials with unique properties not found in bulk materials. The properties of interest depend critically on the structure and composition of the films, with the interfacial regions between the layers being of particular importance. There are a number of magnetic MLF systems based on Co, several of which have potential applications as perpendicular magnetic (e.g Co/Cr) or magneto-optic (e.g. Co/Pt) recording media. Of particular concern are the effects of parameters such as crystallographic texture and interface roughness, which are determined by the fabrication conditions, on magnetic properties and structure.In this study we have fabricated Co-based MLF by UHV thermal evaporation in the prechamber of an atom probe field-ion microscope (AP). The multilayers were deposited simultaneously onto cobalt field-ion specimens (for AP and position-sensitive atom probe (POSAP) microanalysis without exposure to atmosphere) and onto the flat (001) surface of oxidised silicon wafers (for subsequent study in cross-section using high-resolution electron microscopy (HREM) in a JEOL 4000EX. Deposi-tion was from W filaments loaded with material in the form of wire (Co, Fe, Ni, Pt and Au) or flakes (Cr). The base pressure in the chamber was around 8×10−8 torr during deposition with a typical deposition rate of 0.05 - 0.2nm/s.

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Field emission and atom probe field ion microscope studies of palladium-silicide-coated silicon emitters

Journal of Vacuum Science & Technology B Microelectronics Processing and Phenomena ◽

10.1116/1.587923 ◽

1995 ◽

Vol 13 (2) ◽

pp. 603 ◽

Cited By ~ 6

Author(s):

R. A. King

Keyword(s):

Field Emission ◽

Atom Probe ◽

Probe Field ◽

Palladium Silicide ◽

Field Ion Microscope

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Atomic Level Characterization of the Morphology of Phases in Chromindur Magnetic Alloys

MRS Proceedings ◽

10.1557/proc-232-59 ◽

1991 ◽

Vol 232 ◽

Cited By ~ 2

Author(s):

M. K Miller ◽

P. P. Camus ◽

M. G. Hetherington

Keyword(s):

Atom Probe ◽

Heat Treatments ◽

Miscibility Gap ◽

Probe Field ◽

Magnet Alloy ◽

Two Phases ◽

Isothermal Heat Treatments ◽

Field Ion Microscope ◽

Permanent Magnet Alloy

ABSTRACTThe atom probe field ion microscope has been used to characterize the morphology and determine the compositions of the iron-rich a and chromium-enriched α′ phases produced during isothermal and step cooled heat treatments in a Chromindur II ductile permanent magnet alloy. The good magnetic properties of this material are due to a combination of the composition of the two phases and the isolated nature and size of the ferromagnetic a phase. The morphology of the a phase is produced as a result of the shape of the miscibility gap and the step-cooled heat treatment and is distinctly different from that formed during isothermal heat treatments.

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