Paul Aveling Redhead

The Indian Vacuum Society (established in 1970) has organized a symposium every alternate year on various aspects of vacuum science and technology. There has been considerable participation from R & D establishments, universities and Indian industry in this event. In view of the current global scenario and emerging trends in vacuum technology, this year, the executive committee of IVS felt it appropriate to organize an international symposium at Tata Institute of Fundamental Research, Colaba, Mumbai 400 005 from 29–30 November 2007. This symposium provided a forum for exchange of information among vacuum scientists, technologists and industrialists on recent advances made in the areas of large vacuum systems, vacuum production, its measurement and applications in industry, and material processing in vacuum. Vacuum science and technology has made vital contributions in high tech areas like space, high energy particle accelerators, large plasma systems, electronics, thin films, melting and refining of metals, extraction and processing of advanced materials etc.The main areas covered in the symposium were the production and measurement of vacuums, leak detection, large vacuum systems, vacuum metallurgy, vacuum materials and processing inclusive of applications of vacuum in industry. Large vacuum systems for high energy particle accelerators, plasma devices and light sources are of special significance for this symposium. Vacuum evaporation, hard coatings, thin films, joining techniques, sintering, melting and heat treatment, furnaces and thermo dynamics are also covered in this symposium. There were eighteen invited talks from the best experts in the respective fields and more than one hundred contributed papers. This fact itself indicates the interest that has been generated amongst the scientists, technologists and industrialists in this field. In view of the industrial significance of the vacuum technology, an exhibition of vacuum and vacuum processing related equipments, accessories, products etc by different manufacturers and suppliers has been organized at the venue of the symposium hall for the benefit of the participants. The interest shown by the exhibitors reveals that the industry has come of age and the advances that have taken place over the years is quite significant.During the symposium, the Indian Vacuum Society felicitated two distinguished personalities who have contributed significantly for the development of vacuum science and technology in the country. The C AMBASANKARAN memorial and Smt SHAKUNTALABAI VYAWAHARE memorial Awards were also conferred on the two best contributed papers. A committee constituted by the Symposium Organizing Committee evaluated the relevance, scientific content, and clarity of presentation to decide the award winning papers. It is hoped that the discussion generated by the delegates at the symposium will help in a better understanding vacuum science and technology. K C Mittal Convener S K Gupta Co Convener Kakodkar, Anil DAE/India, Chairman Badve, Cdr A.V.(IN Retd.) Pfeiffer Vac India Banerjee, S. BARC/India Bhandari, R.K. BRNS/India Chander, Shekhar CEERI/India Chopra, K.L. IIT Delhi/India Day, Chris ITER Grover, R.B DAE,BARC/India Jakub, Szajman VSA/ Australia Jayaraj, R.N. NFC/India Kamath, H.S. BARC/India Kaw, P.K. IPR/India Kobayashi, M. VSJ/Japan Kumar, Lalit MTRDC, India Kumar, Vikram NPL., India Langley, Robert AVS, USA Larour, Jean Ecole/France Mendonsa, R.H. Lawrence and Mayo Myneni, Ganapatirao Jlab/USA Narsaiah, S.V. HHV Padamsee, Hasan Cornell/USA Pillay, R.G. TIFR Raj, Baldev IGCAR/India Raju, P.T. IVS/India Ramasami, T. DST/India Ray, A.K. BARC/India Reid, RJ IUVSTA/UK Roy, Amit IUAC/india Sahni, V.C. RRCAT, BARC/India Schamiloglu, E. UNM/USA Shankara, K.N. VSSC,ISRO/India Sinha, Bikash VEC,SINP/India Strubin, P. CERN/Switzerland Ray, A.K. BARC (Chairman) Kailas, S. BARC, (Co Chairman) Chakravarty, D.P. BARC Chandrachoodan, P.P. BRNS Desai, Tushar Mumbai Univ. Dhamija, Lokesh BOC Edwards Dixit, Anand New Poona Ind. Gadkari, S.C. BARC Gantayet, L.M BARC Gupta, A.C. NPL Gupta, S.K. BARC (Co Convener) Handu, V.K. BARC Jathar, Rajendra Varian Joshi, S.N. CEERI Korgaonkar, A.V. IVS Kotaiah, S. CAT Kumar, Vijay BARC Matkar, A.W. BARC Mittal, K.C. BARC (Convener) Nema, P.K. BRNS Pandit, V.S. VEC Puranik, S.G. Ashwani Enterprises Puri, R.R. BARC Ranga Rao, Y. Vac. Techniques Sabharwal, Rajat Alcatel Sakhamuri, Prashant HHV Bangalore Sanyal, T. NFC Sarkar, S.K. TIFR Sarma, K.R. Atomic Vacuum Saxena, Y.C. IPR Sharma, B.P. BARC Shukla, S.K. RRCAT Singh, R.P. BARC Suri, A.K. BARC Suthar ,R.L. BARC Venugopa,l V. BARC Vyavahare, Mohan Ultimate Technologies Yakhmi, J.V. BARC

High detection sensitivity in bulk analysis or depth profiling by secondary ion mass spectrometry (SIMS) can only be achieved, for positively charged ions, if the nearsurface regions of the sputter eroded sample are fully oxidized. Using oxygen primary ions, a stationary oxidation state is established after some time of bombardment during which period the sputtering yield decreases and the ionization probability increases. The physical and chemical processes occurring during the transient period are reviewed with emphasis on the results for impurity analysis in silicon, i.e. the matrix material that has been studied most thoroughly in the past. The transient decrease in sputtering yield gives rise to a depth scale offset and an associated apparent shift of impurity profiles towards the surface. The effect is largest at normal beam incidence, ca. 1 nm /keV (O + 2 ), in which case silicon is fully oxidized. The transition depth, i.e. the depth sputtered before achieving a stable ion yield is about twice as large and increases as the impact angle is turned away from normal. The shift and the depth scale offset can be measured safely using thin (delta) layers of isotopically pure tracers, for example 30 Si in 28 Si. Boron delta layers can serve as secondary standards because this impurity behaves almost the same as the host silicon atoms. The profile shift observed with other common dopants may contain contributions due to unidirectional relocation, often driven by segregation away from the surface. At O + 2 energies below about 0.7 keV the transition depths fall below the thickness of typical native oxides, so that the transient changes in sputtering yield and ionization probability can disappear. The transient phenomena may be described by a simple sputtering-oxidation model that connects the depth scale offset to other observable parameters like the initial and final sputtering yield, the transition fluence and the oxide thickness.

CHAPTER 1 - Units and Terminology in Vacuum Technology

The history of vacuum technology was analyzed by a “discovery-incubation-new industry” model. In the present third cycle, surface analysis and surface science have been emerged along with the advent of ultra-high vacuum technology. The future trend of surface science was discussed.

In Memoriam: Dr. Clive L. Dym (1942–2016)

The educational program in vacuum and surface science at UWM involves a number of different components. Core courses are required of all graduate students who major in surface science. These courses include a semester of Vacuum Science and Technology, a year review of experimental and theoretical approaches in Surface Physics and a year of Surface Chemistry. In addition, a number of specialized courses on specific topics are available. Further educational opportunities are provided by the biennial International Summer Institute in Surface Science, at which invited speakers provide tutorials on the state of the art of various areas in Surface Science. The annual E. W. Muller Lectureship features a summer course in a selected topic by an internationally known expert. Weekly seminars provide opportunities for graduate students, post‐docs, faculty and visitors to meet and exchange information. Graduating students here have thus been exposed to a considerable quantity of course work which, in combination with ...

The 60th International Conference on Electron, Ion, and Photon Beam Technology and Nanofabrication (EIPBN) was held in Pittsburgh, PA, from May 31st to June 3rd, 2016. The conference received technical co-sponsorship from the American Vacuum Society (AVS) in cooperation with the Optical Society of America (OSA), and the American Physical Society (APS). The conference was a great success in large part because financial support allowed robust participation from students. The students gave oral and poster presentations of their research and many published peer-reviewed articles in a special conference issue of the Journal of Vacuum Science and Technology B. The Department of Energy Office of Basic Energy Sciences supported 10 students from US universities with a $5,000 grant (DE-SC0015555).

Applications of semiconductor sputter profiling in the near future will demand nm or even sub-nm depth resolution, i.e. the ability to distinguish between adjacent features in a concentration profile which are separated by 1 nm or less (not just the ability to achieve a 16-84% width of 1 nm on some edge transient). Recent developments in SIMS indicate that sputter profiling can meet this challenge—provided that instruments with high current microfocus beams less than 1 keV in energy become widely available, and data processing methods are developed to cope with the results. In this paper we discuss the nature of SIMS sputter profile data in detail and explore the consequences of noise, finite sample interval and the destruction of information by processes such as atomic mixing. The use of empirically determined response functions is discussed. We use simple arguments to show that convolution is only a valid model for atomic mixing in the low concentration limit, and contrast the use of Fourier transform and maximum entropy methods for deconvolution in these circumstances. A depth resolution of 1 nm is demonstrated without deconvolution, showing that the technique has real potential for depth resolution on the scale of 1 atomic plane.

Vacuum science and technology: Pioneers of the 20th century: Edited by Paul A Readhead History of vacuum science and technology, Vol 2. American Institute of Physics, for the American Vacuum Society, New York, 1994. ISBN 1-56396-248-9, $35.00

“50 Years of Varian sputter ion pumps and new technologies”

Gert Ehrlich, who made important contributions to surface science, especially in the area of atomic interactions on solid surfaces, died of leukemia on 10 August 2012 in Urbana, Illinois. Up to five weeks before his death, he worked tirelessly as a professor in the materials science department at the University of Illinois at Urbana-Champaign. He coauthored more than 200 scientific articles and the book Surface Diffusion: Metals, Metal Atoms, and Clusters (Cambridge University Press, 2010).Gert was born on 22 June 1926 in Vienna. After Germany annexed Austria in 1938, Gert and his father, who was Jewish (his mother was Catholic), were detained for questioning but, luckily, released. His father immediately departed for the US, and in May 1939 Gert and his sister, Dorothy, arrived unescorted in New York on the T.S.S. Veendam and were reunited with their father. What might have been a harrowing voyage had become a grand adventure: Gert had investigated all aspects of the ship’s operation and explored the ship from top to bottom. His mother joined the family several months later.In 1944 Gert enrolled at Columbia University. He served in the US Army from 1945 to 1947 and then returned to graduate from the university with honors in chemistry in 1948. He obtained his PhD in chemistry from Harvard University in 1952 under adviser Paul Doty; his thesis title was “Studies on synthetic polyampholytes.” Gert remained at Harvard for a year as a National Institutes of Health fellow. He then served a year as a research associate in the University of Michigan physics department, where he worked with Gordon Sutherland on IR spectroscopy of macromolecules.In 1953 Gert accepted a full-time appointment at the General Electric Research Laboratory in Schenectady, New York, where he studied the kinetics of gas–solid interactions. He developed temperature-programmed, or flash, desorption techniques for quantitative kinetic studies at the gas–solid interface and demonstrated the importance of distinct binding sites in chemisorption phenomena.The field ion microscope, invented in 1951 by Erwin Müller, enabled Gert to probe the underlying atomic details of his macroscopic observations. Gert made unique chemisorption studies on single-crystal surfaces and the first quantitative observations of individual atoms diffusing on a metal surface. His resulting 1966 article with Frank Hudda in the Journal of Chemical Physics has been cited more than 1000 times.Gert accepted a professorship at the University of Illinois in 1968. Leading a small group of graduate students and postdocs, he expanded his research toward surface studies on an atomic scale. Using an atom-probe field ion microscope, Gert and his group made the first direct observation of an adatom exchange mechanism. They observed and characterized numerous aspects of surface diffusion, including interior step-edge barriers, reflective plane-edge barriers, adatom–vacancy interactions, temperature-dependent long jumps, and adatom cluster motion. Gert and his group used a variety of theoretical and experimental methods to study atomic behavior and transformed the apparently hopelessly complicated subject of surface diffusion at the atomic scale into one much more understandable and explainable.Among the several honors Gert received were the 1979 Medard W. Welch Award from the American Vacuum Society and the 1982 American Chemical Society Award in Colloid and Surface Chemistry. Through a 1992 research award from the German Alexander von Humboldt Foundation, he worked on boundary layer chemistry and interfacial chemistry at the Fritz Haber Institute in Berlin with Gerhard Ertl and Jochen Block.Gert was an extremely careful and extraordinarily attentive researcher, with the highest achievable vacuum and precise timing and temperature controls. Gert also was merciless in the proper statistical analysis of data—no small task in the early slide-rule days when access to a computer meant a time-sharing connection on a teletype at 10 characters per second.Perhaps Gert’s most endearing characteristic was his concern for students. His door was always open. When a student would stop by with a question, Gert usually answered with another question to challenge the student. He established a mentoring system in which current students taught the necessary know-how and unpublished techniques to incoming students. When not in the lab, he could easily be found: As he wandered the halls, he would produce a low, enigmatic, warbling whistle, usually his unique rendering of a classical opera aria.Gert was a curious scientist, and his precise work on the behavior of atoms on surfaces was foundational to modern nanoscience and technology. He also was an excellent teacher who compulsively prepared every lecture, even on material he had previously taught. On receiving news about the success of a former student, he would sport a generous grin and his eyes would sparkle.Gert EhrlichPPT|High resolution© 2013 American Institute of Physics.

We investigated nanoparticle electrocatalysts in oxygen evolution reaction (OER) and CO2 reduction reaction (CO2RR) via an approach coupling electrochemistry with ultra-high vacuum (UHV) surface science and computational modeling. Well-defined nanoparticle electrocatalysts such as Fe2O3, NiFeOx, and Ag, were prepared in the UHV chamber via physical vapor deposition (PVD) and characterized with surface science techniques including X-ray photoelectron spectroscopy (XPS) and scanning tunneling microscopy (STM), followed by electrochemistry measurements to establish the structure-property relationships in OER and CO2RR. Calculations based on density functional theory (DFT) and microkinetic modeling (MKM) were then implemented to gain fundamental insight into these systems. We observed the edge-enhanced OER activity of Au-supported, ultra-thin Fe2O3 electrocatalysts and revealed incorporation of Ni at the edge sites (NiFeOx) further boosting their OER activity. We also resolved the size-dependent transition between CO2RR and H2 evolution reaction (HER) selectivity in sub-5 nm Ag electrocatalysts and identified an effective minimum size limit of ∼4 nm for active and selective Ag catalysts: particle diameters below this range experienced increased H2 evolutions due to a high population of Ag edge sites; and larger diameter particles favored CO2RR as the population of Ag(100) surface sites grew but will begin to lose catalyst utilization based on total metal masses.

At Union Carbide Corporation, surface science and fundamental studies have played extremely important roles in the discovery, development, and diagnosis of several valuable commercial and developmental catalyst systems. Prior to the late '60s, it was very common among scientists and engineers to refer to catalysis, particularly heterogeneous catalysis, as either an “art” or “magic”. Primary reasons behind these labels were our inability to understand the performance of “poor” and “good” catalysts nominally having the same bulk composition. With the development of surface science in the early '70s, heterogeneous catalysis field was relatively easy picking for diagnosis and improved understanding of many of these poorly understood catalyst systems. In fact, there were many “sad” stories across the chemical industry of catalysts that prematurely deactivated or essentially died and there was no known cause or relationship of performance with observable physical–chemical properties. In all such instances, the bulk characterization techniques failed to identify or uncover the cause or causes of such activity decline. However, through the use of surface science and fundamental characterizations, three such “sad stories” turned into “success stories” at Union Carbide. In addition, it will also be shown that the early use of surface science and fundamental studies led to the discovery, development and enhanced understanding of several catalyst systems. Many of the early surface science techniques along with the newly developed techniques continue to and will play a very important role in the future development of next generation catalysts and catalytic processes for the industrial use and environmental protection.

A simple temperature control system for ultrahigh vacuum (UHV) surface science applications has been developed. It is based on commercially available components and can be constructed with minimal electronics expertise. It controls the temperature of a single crystal sample in UHV over the range 80–1633 K using a type K thermocouple to monitor the temperature of the sample. The controller can be used to provide temperature ramps over the range 0–10 K/s.

Abstract