SCIENCEA Brief & METROLOGY History SOLUTIONS of Atom Probe Thomas F. Kelly and John A. Panitz Pre-meeting Congress, M&M 2016 SCIENCE & METROLOGY SOLUTIONS & METROLOGY SCIENCE www.cameca.com Ancestry of the Modern Atom Probe SCIENCE & METROLOGY SOLUTIONS SCIENCE & METROLOGY SOLUTIONS & METROLOGY SCIENCE A Brief History of Atom Probe July 24, 2016 2 Erwin Wilhelm Müller SCIENCE & METROLOGY SOLUTIONS SCIENCE & METROLOGY SOLUTIONS & METROLOGY SCIENCE Photograph of Professor Erwin W. Müller (1911-1977): Father of High Field Nanoscience A Brief History of Atom Probe July 24, 2016 3 Field Electron Emission Microscopy 1935 - electron SCIENCE & METROLOGY SOLUTIONS Fluorescent Screen ̶ E + SCIENCE & METROLOGY SOLUTIONS & METROLOGY SCIENCE E. W. Müller, Z. Phys. 120 (1943) 270 A Brief History of Atom Probe July 24, 2016 4 Field Electron Emission Microscopy ■ Field electron emission microscopy (FEEM) was developed as a point projection microscope ■ FEEM patterns showed clear crystallographic information ■ Ba atoms and phthalocyanine molecules were observed on W needlesSCIENCE with FEEM & METROLOGY SOLUTIONS ■ Image resolution improved through the late 1940’s ■ Müller sought to resolve atoms with FEEM ■ Eventually it was concluded that FEEM would resolve no better than ~2 nm ■ Field desorption (and evaporation?) was shown in 1941 SCIENCE & METROLOGY SOLUTIONS & METROLOGY SCIENCE A Brief History of Atom Probe July 24, 2016 5 Field Ion Microscopy • FEEM tips were routinely cleaned by reversing the bias • Practitioners of FEEM noticed: • Field ions were emitted during reverse bias • Müller sought, and found, a way to increase the signal of field ions: H, He gas SCIENCE & METROLOGY SOLUTIONS • Intensity of field ion signal varied with gas pressure • In early 1950s, this was pursued for imaging the tip surface • Atoms at ledges were seen • Early field ion images (FIM) had Erwin Müller at Penn State SOLUTIONS & METROLOGY SCIENCE higher resolution than FEEM A Brief History of Atom Probe July 24, 2016 6 Field Ion Microscopy 1951 Gas supply + ion SCIENCE & METROLOGY SOLUTIONS Fluorescent Screen + E ̶ First images ever of atoms (on ledges of tip surface): Summer 1951, Müller First atomically resolved lattice on surface: October 11, 1955, Bahadur and Müller SOLUTIONS & METROLOGY SCIENCE A Brief History of Atom Probe July 24, 2016 7 Imaging Crystal Defects in FIM ■ Surface atoms and defects are visible in FIM ■ E.g. Self-interstitial atoms produce large image in FIM SCIENCE & METROLOGY SOLUTIONS SCIENCE & METROLOGY SOLUTIONS & METROLOGY SCIENCE A Brief History of Atom Probe July 24, 2016 8 Vacancies imaged in FIM! ■ Vacancies observed ■ Knock-on damage cascades were mapped by cinematography of FIM SCIENCE & METROLOGY SOLUTIONS SCIENCE & METROLOGY SOLUTIONS & METROLOGY SCIENCE A Brief History of Atom Probe July 24, 2016 9 1960s FIM SCIENCE & METROLOGY SOLUTIONS SCIENCE & METROLOGY SOLUTIONS & METROLOGY SCIENCE A Brief History of Atom Probe July 24, 2016 10 40 K Tungsten Best Imaging Needle Voltage Helium Gas Slight Laser Phosphor FIM & Field Heating Screen Field Evaporation Evaporation Movie Adsorbed gas atoms ⇒ field ion image Specimen atoms ⇒ atom probe Movie Courtesy Baptiste Gault 3D FIM Comes to Life! • 100% of atoms positioned • High precision on atom locations • Crystal structure and defects readily SCIENCE & METROLOGY SOLUTIONS visible SCIENCE & METROLOGY SOLUTIONS & METROLOGY SCIENCE A Brief History of Atom Probe July 24, 2016 12 Compositional Contrast in FIM SCIENCE & METROLOGY SOLUTIONS In this field ion micrograph of boron-doped nickel aluminide (Ni3Al), the bright dots are individual SOLUTIONS & METROLOGY SCIENCE boron atoms that have segregated to a grain boundary (arrowed). A Brief History of Atom Probe July 24, 2016 13 The Atom Probe ■ Müller sought a way to identify atoms in the specimen ■ Barofsky was asked to built a magnetic sector mass spectrometer ■ He later suggested that they should try ToF ■ Panitz was assigned the job SCIENCE & METROLOGY SOLUTIONS ■ How to detect single atoms? Never been done John A. Panitz Mueller, Panitz, McLane, Rev. Sci. Instrum. (1968) vol. 39, p. 83. SOLUTIONS & METROLOGY SCIENCE A Brief History of Atom Probe July 24, 2016 14 Much of the following from Panitz 2014 SCIENCE & METROLOGY SOLUTIONS 54th International Field Emission Symposium Atom Probe Tomography and Microscopy Stuttgart, Germany 2014 SOLUTIONS & METROLOGY SCIENCE A Brief History of Atom Probe July 24, 2016 15 The Müller Group ~ 1968 SCIENCE & METROLOGY SOLUTIONS Names in bold are part of the atom probe effort SCIENCE & METROLOGY SOLUTIONS & METROLOGY SCIENCE A Brief History of Atom Probe July 24, 2016 16 Original Atom-Probe Field Ion Microscope 1967 SCIENCE & METROLOGY SOLUTIONS SCIENCE & METROLOGY SOLUTIONS & METROLOGY SCIENCE A Brief History of Atom Probe July 24, 2016 17 Single Atom Detection Was Invented SCIENCE & METROLOGY SOLUTIONS Photograph of oscilloscope screen SCIENCE & METROLOGY SOLUTIONS & METROLOGY SCIENCE A Brief History of Atom Probe July 24, 2016 18 Data File: Oscilloscope Trace Polaroid picture of oscilloscope screen Atom Hit SCIENCE & METROLOGY SOLUTIONS SCIENCE & METROLOGY SOLUTIONS & METROLOGY SCIENCE A Brief History of Atom Probe July 24, 2016 19 First Publication on Atom Probe SCIENCE & METROLOGY SOLUTIONS SCIENCE & METROLOGY SOLUTIONS & METROLOGY SCIENCE A Brief History of Atom Probe July 24, 2016 20 The Second Atom Probe - 1968 SCIENCE & METROLOGY SOLUTIONS SCIENCE & METROLOGY SOLUTIONS & METROLOGY SCIENCE A Brief History of Atom Probe July 24, 2016 21 Muller and Panitz A Brief History of Atom Probe July 24, 2016 22 Imaging Atom Probe: the Progenitor of Atom Probe Tomography ■ MRP of 14 was achieved! SCIENCE & METROLOGY SOLUTIONS ■ Tip tilting not needed ■ Flight distance 11.38 cm to center ■ Observe field ion image or field desorption image ■ Mass analyze all atoms within a field of view SOLUTIONS & METROLOGY SCIENCE A Brief History of Atom Probe July 24, 2016 23 Imaging Atom Probe 2.0: Curved MCPs ■ Tip at center of MCP curvature ■ All parts of detector have same flight length ■ High mass resolution over entire field of view SCIENCE & METROLOGY SOLUTIONS ■ Tomographic imaging possible Detector technology for recording each ion impact position was not yet invented SOLUTIONS & METROLOGY SCIENCE A Brief History of Atom Probe July 24, 2016 24 Field Desorption Images of Single Specie SCIENCE & METROLOGY SOLUTIONS ■ Time gate on MCPs SCIENCE & METROLOGY SOLUTIONS & METROLOGY SCIENCE A Brief History of Atom Probe July 24, 2016 25 Pulsed Laser Atom Probe ■ A laser was adapted to the Imaging atom probe at Sandia Laboratories ■ First time non-metals were atom probedSCIENCE & METROLOGY SOLUTIONS ■ Laser pulsing has become the dominant pulsing mode in APT SCIENCE & METROLOGY SOLUTIONS & METROLOGY SCIENCE A Brief History of Atom Probe July 24, 2016 26 PLAP data - Molybdenum ■ Flight path was not optimized ■ No correction for flight distance across detector ■ DemonstratedSCIENCE laser & METROLOGY SOLUTIONS pulsing for metals, insulators ■ Correct isotopic abundances SCIENCE & METROLOGY SOLUTIONS & METROLOGY SCIENCE A Brief History of Atom Probe July 24, 2016 27 New Groups Develop – University of Oxford SCIENCE & METROLOGY SOLUTIONS Professor George Smith Congratulations to George MSA Distinguished Scientist Award First atom probe expert SCIENCE & METROLOGY SOLUTIONS & METROLOGY SCIENCE Early atom probe at Oxford A Brief History of Atom Probe July 24, 2016 28 The Vacuum Generators APFIM 100 1975 SCIENCE & METROLOGY SOLUTIONS ■ Developed in conjunction with Smith et al. at Oxford ■ First commercial atom probe SOLUTIONS & METROLOGY SCIENCE A Brief History of Atom Probe July 24, 2016 29 The Position-Sensitive Atom Probe 1988 ■ Adapted a Wedge-and-Strip detector from astronomy to a VG APFIM 100 ■ 1988 Fall MRS presentedSCIENCE by & METROLOGY SOLUTIONS George Smith ■ First operational 3DAP SCIENCE & METROLOGY SOLUTIONS & METROLOGY SCIENCE A Brief History of Atom Probe July 24, 2016 30 The Position-Sensitive Atom Probe (PoSAP) SCIENCE & METROLOGY SOLUTIONS SCIENCE & METROLOGY SOLUTIONS & METROLOGY SCIENCE A Brief History of Atom Probe July 24, 2016 31 The Commercial PoSAP SCIENCE & METROLOGY SOLUTIONS SCIENCE & METROLOGY SOLUTIONS & METROLOGY SCIENCE Manufactured by Kindbrisk (Oxford NanoScience) A Brief History of Atom Probe July 24, 2016 32 Tomographic Atom Probe SCIENCE & METROLOGY SOLUTIONS D. Blavette, A. Bostel, J. M. Sarrau, B. Deconihout, and A. Menand: An atom-probe for three dimensional SOLUTIONS & METROLOGY SCIENCE tomography. Nature 363:432–435 (1993). A Brief History of Atom Probe July 24, 2016 33 TAP Detector SCIENCE & METROLOGY SOLUTIONS SCIENCE & METROLOGY SOLUTIONS & METROLOGY SCIENCE A Brief History of Atom Probe July 24, 2016 34 Electron-Beam-Pulsed Atom Probe ■ Thermal pulsing can be route to high repetition rates ■ Need to heat very small volumes for rapid cooling ■ Needed for high mass resolving power SCIENCE & METROLOGY SOLUTIONS ■ Electron beams can be focused to very small diameter ■ ~100 nm heated volume ■ Specimen in atom probe is positive electrode ■ Thermal pulsing with electron beam SOLUTIONS & METROLOGY SCIENCE A Brief History of Atom Probe July 24, 2016 35 Atom Probe and (S)TEM ■ Electron beam pulsing and atom probe naturally suggest imaging during analysis ■ There are manySCIENCE & METROLOGY SOLUTIONS advantages of having a TEM image of the specimen Kelly, 1990 IFES meeting, Albuquerque SOLUTIONS & METROLOGY SCIENCE A Brief History of Atom Probe July 24, 2016 36 Electron-Beam-Pulsed Atom Probe