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The atom probe was introduced at the 14th Field Emission Symposium in 1967 by Erwin Wilhelm Müller and J. A. Panitz. It combined a field ion microscope with a mass spectrometer having a single particle detection capability and, for the first time, an instrument could “... determine the nature of one single atom seen on a metal surface and selected from neighboring atoms at the discretion of the observer”.
A cathode is the electrode from which a conventional current leaves a polarized electrical device. This definition can be recalled by using the mnemonic CCD for Cathode Current Departs. A conventional current describes the direction in which positive charges move. Electrons have a negative electrical charge, so the movement of electrons is opposite to that of the conventional current flow. Consequently, the mnemonic cathode current departs also means that electrons flow into the device's cathode from the external circuit. For example, the end of a household battery marked with a + (plus) is the cathode.
The Field ion microscope (FIM) was invented by Müller in 1951. It is a type of microscope that can be used to image the arrangement of atoms at the surface of a sharp metal tip.
A scanning electron microscope (SEM) is a type of electron microscope that produces images of a sample by scanning the surface with a focused beam of electrons. The electrons interact with atoms in the sample, producing various signals that contain information about the surface topography and composition of the sample. The electron beam is scanned in a raster scan pattern, and the position of the beam is combined with the intensity of the detected signal to produce an image. In the most common SEM mode, secondary electrons emitted by atoms excited by the electron beam are detected using a secondary electron detector. The number of secondary electrons that can be detected, and thus the signal intensity, depends, among other things, on specimen topography. Some SEMs can achieve resolutions better than 1 nanometer.
Timeline of microscope technology
Transmission electron microscopy (TEM) is a microscopy technique in which a beam of electrons is transmitted through a specimen to form an image. The specimen is most often an ultrathin section less than 100 nm thick or a suspension on a grid. An image is formed from the interaction of the electrons with the sample as the beam is transmitted through the specimen. The image is then magnified and focused onto an imaging device, such as a fluorescent screen, a layer of photographic film, or a sensor such as a scintillator attached to a charge-coupled device.
Field electron emission, also known as field emission (FE) and electron field emission, is emission of electrons induced by an electrostatic field. The most common context is field emission from a solid surface into a vacuum. However, field emission can take place from solid or liquid surfaces, into a vacuum, a fluid, or any non-conducting or weakly conducting dielectric. The field-induced promotion of electrons from the valence to conduction band of semiconductors can also be regarded as a form of field emission. The terminology is historical because related phenomena of surface photoeffect, thermionic emission and "cold electronic emission", i.e. the emission of electrons in strong static electric fields, were discovered and studied independently from the 1880s to 1930s. When field emission is used without qualifiers it typically means "cold emission".
Scanning probe microscopy (SPM) is a branch of microscopy that forms images of surfaces using a physical probe that scans the specimen. SPM was founded in 1981, with the invention of the scanning tunneling microscope, an instrument for imaging surfaces at the atomic level. The first successful scanning tunneling microscope experiment was done by Gerd Binnig and Heinrich Rohrer. The key to their success was using a feedback loop to regulate gap distance between the sample and the probe.
In vacuum tubes and gas-filled tubes, a hot cathode or thermionic cathode is a cathode electrode which is heated to make it emit electrons due to thermionic emission. This is in contrast to a cold cathode, which does not have a heating element. The heating element is usually an electrical filament heated by a separate electric current passing through it. Hot cathodes typically achieve much higher power density than cold cathodes, emitting significantly more electrons from the same surface area. Cold cathodes rely on field electron emission or secondary electron emission from positive ion bombardment, and do not require heating. There are two types of hot cathode. In a directly heated cathode, the filament is the cathode and emits the electrons. In an indirectly heated cathode, the filament or heater heats a separate metal cathode electrode which emits the electrons.
Focused ion beam, also known as FIB, is a technique used particularly in the semiconductor industry, materials science and increasingly in the biological field for site-specific analysis, deposition, and ablation of materials. A FIB setup is a scientific instrument that resembles a scanning electron microscope (SEM). However, while the SEM uses a focused beam of electrons to image the sample in the chamber, a FIB setup uses a focused beam of ions instead. FIB can also be incorporated in a system with both electron and ion beam columns, allowing the same feature to be investigated using either of the beams. FIB should not be confused with using a beam of focused ions for direct write lithography. These are generally quite different systems where the material is modified by other mechanisms.
Erwin Wilhelm Müller was a German physicist who invented the Field Emission Electron Microscope (FEEM), the Field Ion Microscope (FIM), and the Atom-Probe Field Ion Microscope. He and his student, Kanwar Bahadur, were the first people to experimentally observe atoms.
George David William Smith FRS, FIMMM, FInstP, FRSC, CEng is a materials scientist with special interest in the study of the microstructure, composition and properties of engineering materials at the atomic level. He invented, together with Alfred Cerezo and Terry Godfrey, the Atom-Probe Tomograph in 1988.
John A. Panitz is Emeritus Professor of Physics at the University of New Mexico in Albuquerque. During his tenure at UNM he was Professor of Physics, Professor of High Technology Materials and Professor of Cell Biology and Physiology. Professor Panitz developed the first laboratory courseware that encouraged both critical thinking and role playing in the structured environment of a cooperative learning group. Before joining UNM Professor Panitz was in the Surface Science Division at Sandia National Laboratory in Albuquerque where he patented the Field Desorption Spectrometer and the LiFE Detector. He is the founder and CEO of High Field Consultants and the owner and curator of Gallerie Imaginarium.
Sputter deposition is a physical vapor deposition (PVD) method of thin film deposition by the phenomenon of sputtering. This involves ejecting material from a "target" that is a source onto a "substrate" such as a silicon wafer. Resputtering is re-emission of the deposited material during the deposition process by ion or atom bombardment. Sputtered atoms ejected from the target have a wide energy distribution, typically up to tens of eV. The sputtered ions can ballistically fly from the target in straight lines and impact energetically on the substrates or vacuum chamber. Alternatively, at higher gas pressures, the ions collide with the gas atoms that act as a moderator and move diffusively, reaching the substrates or vacuum chamber wall and condensing after undergoing a random walk. The entire range from high-energy ballistic impact to low-energy thermalized motion is accessible by changing the background gas pressure. The sputtering gas is often an inert gas such as argon. For efficient momentum transfer, the atomic weight of the sputtering gas should be close to the atomic weight of the target, so for sputtering light elements neon is preferable, while for heavy elements krypton or xenon are used. Reactive gases can also be used to sputter compounds. The compound can be formed on the target surface, in-flight or on the substrate depending on the process parameters. The availability of many parameters that control sputter deposition make it a complex process, but also allow experts a large degree of control over the growth and microstructure of the film.
Jonathan Harris Orloff is an American physicist, author and professor. Born in New York City, he is the eldest son of Monford Orloff and brother of pianist Carole Orloff and historian Chester Orloff. Orloff is known for his major fields of research in charged particle optics, applications of field emission processes, high-brightness electron and ion sources, focused ion and electron beams and their applications for micromachining, surface analysis and microscopy and instrumentation development for semiconductor device manufacturing.
S. Brooks McLane was the electronic technician in the Field Emission Laboratory at Penn State who, with Gerald Fowler and J. A. Panitz was responsible for developing the Atom-Probe Field Ion Microscope. An electronics specialist who received an M.S. degree from the Texas School of Arts and Industries, he was Assistant Professor of Physics at Davidson College in 1957 and co-authored several scientific papers including "Field Absorption and desorption of helium and neon" that appeared in Surface Science in 1969. Between 1964 and 1986 he co-wrote 8 separate articles in his field that appeared in the American Institute of Physics' Review of Scientific Instruments.
Field-emission microscopy (FEM) is an analytical technique used in materials science to investigate molecular surface structures and their electronic properties. Invented by Erwin Wilhelm Müller in 1936, the FEM was one of the first surface-analysis instruments that approached near-atomic resolution.
Gerald Leroy Fowler was a veteran of World War II, the lead technician in the Field Emission laboratory at the Pennsylvania State University and was a master technician in the Surface Science division at Sandia National Laboratories in Albuquerque, New Mexico. He was the author or co-authored of nine technical publications in refereed journals.
The MIAMI facility is a scientific laboratory located within the Ion Beam Centre at the University of Huddersfield. This facility is dedicated to the study of the interaction of ion beams with matter. The facilities combine ion accelerators in situ with Transmission Electron Microscopes (TEM): a technique that allows real-time monitoring of the effects of radiation damage on the microstructures of a wide variety of materials. Currently the laboratory operates two such systems MIAMI-1 and MIAMI-2 that are the only facilities of this type in the United Kingdom, with only a few other such systems in the world. The MIAMI facility is also part of the UKNIBC along with the Universities of Surrey and Manchester, which provides a single point of access to a wide range of accelerators and techniques.
A probe tip is an instrument used in scanning probe microscopes (SPMs) to scan the surface of a sample and make nano-scale images of surfaces and structures. The probe tip is mounted on the end of a cantilever and can be as sharp as a single atom. In microscopy, probe tip geometry and the composition of both the tip and the surface being probed directly affect resolution and imaging quality. Tip size and shape are extremely important in monitoring and detecting interactions between surfaces. SPMs can precisely measure electrostatic forces, magnetic forces, chemical bonding, Van der Waals forces, and capillary forces. SPMs can also reveal the morphology and topography of a surface.
References
- ↑ "Background". High Field Consultants. Retrieved 23 May 2022.
- ↑ Müller, Erwin W.; Panitz, John A.; McLane, S. Brooks (1968). "The Atom-Probe Field Ion Microscope". Review of Scientific Instruments. 39 (1): 83–86. Bibcode:1968RScI...39...83M. doi:10.1063/1.1683116. ISSN 0034-6748.
- ↑ Panitz, John A. (1999). "Isothermal ramped field-desorption of benzene from tungsten". Journal of Vacuum Science and Technology. 16 (3): 868–874. Bibcode:1979JVST...16..868P. doi:10.1116/1.570103.
- ↑ Panitz, John A. (1986). "Field-Ion Tomography". In A. D. Romig and W. F. Chambers (ed.). Microbeam Analysis-1986. San Francisco, CA: San Francisco Press. pp. 196–198.
- ↑ Condon, G. R.; Panitz, John A. (1998). "Nanoscale imaging of the electronic tunneling barrier at a metal surface". Journal of Vacuum Science and Technology B. 16 (1): 23–29. Bibcode:1998JVSTB..16...23C. doi:10.1116/1.589787.