AVS Historical Persons
| Charles B. Duke - 1998
Charles B. Duke - 1998
Oral History Interview with Charles B. Duke
Medard W. Welch Award
May or June 1998
I'm Charlie Duke. We are here in the Xerox Wilson Center for Research and Technology in Rochester, New York. I work for the Xerox Corporation. I'm Vice President and Senior Research Fellow here at the Wilson Center. I'm speaking today with Jim Lafferty, who has come here to interview me for the archives of the American Vacuum Society. I thought what I would share with you today is some thoughts about what happened in the Vacuum Society in the '70s and '80s, and how those events have profoundly changed not only the Society but the world in which we live.
To establish the context, one of the things that I did in preparation for this session with you is that I read this book1
on the History of the Vacuum Science and Technology [holds up book]. There is a wonderful article in here, the first article, which is written by Jack Singleton. It's called "The American Vacuum Society at 40." That was a book that was published some years ago at the 40th anniversary of the American Vacuum Society, and it sets out the context in which the Vacuum Society was founded and in which it grew and prospered.
My restatement of the essential elements of that history would be that in the decade of the '50s, the society had its beginnings. In the decade of the '60s, I would call it the Era of Vacuum Technology. This was an era when we went from glass vacuum technology to large metal cans and to vacuum technology in the form essentially that we know it today.
Then in the '70s, another major transformation of the Vacuum Society occurred. I will call it the Era of Surface Science. This, basically, was the era in which the American Vacuum Society really ceased to be a small technological society and became a major national prominent scientific society.
Then in the 1980s, I would call that the Era of Microelectronics. The Electronic Materials and Processing Division was formed. Section B of the Journal of Vacuum Science and Technology was formed to focus on microelectronics and processing. Of course, the instrumentation associated with the surface science and with all kinds of vacuum instrumentation profoundly changed as we wound up with microelectronics and computers, and computing came into every aspect of our experimental life. Of course, it was the era of cheap computing. I used to do low-energy electron diffraction calculations. At the beginning of the 1980s, to do a calculation for gallium arsenide (110) cost approximately $1,500; by the end of that decade, that same calculation cost $150; and today I can do it on my PC. So that was what happened in the decade of the '80s.
The decade of the '90s I've called the Information Era. This basically is the era of computer control of everything. And of course, the AVS has gone on the web.
I was a major player basically in the surface science and the microelectronic eras. I will split up this talk into two separate pieces. I will first talk a little bit about the scientific work that I did during that period, which led to my being awarded the Welch Award in 1977. Then I'll talk a little bit about the activities that I did as an officer in the Vacuum Society and a member of the Board of Directors focusing on the activities that occurred as I was President in 1979.
My first involvement with the American Vacuum Society came in the form of an invited paper on the "Electronic Structure of Clean Metallic Interfaces" given at the Seattle meeting in 1968. That paper, which later became quite famous [holds paper], was an early attempt to apply what is now known as density-functional theory to provide a description of the electronic charge distribution of surfaces. It was one of the first approaches of density-function theory to surfaces and was the harbinger of what is now a routine body of work coming out of many different laboratories where people use this theory to calculate the atomic geometry and the electronic structure of almost any surface of almost any material. Indeed, this is a few days after the Nobel Prizes for 1998 were announced, and I found it very interesting that Walter Kahn won the Nobel Prize in chemistry for the development of this theory.
The work during the era, which led to my receipt of the Welch Award is described in an address that I gave on the occasion of that award called "Electron-Solid Interactions: Their Nature and Consequences", in which I discuss some of the important ideas that were being developed during that decade. One of the very important ideas is associated with the notion that an electron, as it traverses a solid, if it is reasonably fast—by reasonably fast, I mean between 50 volts and maybe a few kilovolts—then it doesn't go very far, say eight to ten angstroms before it emits a plasmon and loses energy. This observation was basically known way back in the early '50s, but its consequences were not really appreciated. Because that means that if you look at electrons that have been scattered elastically from surfaces or had only one or two inelastic losses, they must come from the surface region of the crystal. This was the clue that led to a quantitative theory of the diffraction of electrons by crystals, called Low Energy Electron Diffraction, which has subsequently, because of cheap computing, become the routine surface structure spectroscopy associated with all surfaces. The inelastic collision damping is also responsible, as you all know, these days for the surface sensitivity of Auger spectroscopy or for photoemission spectroscopy. So this really was a very profound change in point of view, which occurred during the early '70s.
The combination of this change in point of view, which led people to realize that many spectroscopies that they previously had thought of as describing the bulk in fact really described the surface. Together with these new vacuum experimental techniques, which I was describing earlier, led to a whole host of surface analytical techniques being developed in the early '70s which completely transformed the landscape. In 1970, if you wanted to look at a surface, you could not find out what was on the surface, you could not find out where it was, and you certainly couldn't find out how it was moving or something about its chemistry. Because of the techniques and the theories that were introduced in that decade, now all of those questions can be answered routinely by even a student in a laboratory in any university or college in the country. So this tremendous transformation occurred during the 1970s from the Vacuum Society as a group of folks who were interested in and developed new vacuum instrumentation and vacuum techniques into a scientific society that was predominantly associated with turning the study of surface from an art form into a science.
One of the specific things that I was involved in, as I indicated, was writing a quantum field theory of the scattering of low-energy electrons from solids, where you let them scatter elastically from the solid and let them generate plasmons or other inelastic events, working out that quantum field theory exactly and applying it to both elastic and inelastic electron solid scattering. The elastic scattering we studied to find out the atomic geometries of these materials. We determined some of the very first atomic geometries that were known, for aluminum and for gallium arsenide. In the case of the inelastic scattering, we learned to invert the analysis of the scattering experiments to determine the energy momentum relation of surface plasmons. In our particular case, we did it for surface plasmons from the low index faces of aluminum. So these were exciting times, understanding the nature of how electrons interacted with solids and learning how to quantitatively analyze the various experiments that were performed in order to determine the spectroscopic characterization of the surface and the atomic geometry of the surface.
Another event that I was involved in at these times was the notion of resonant tunneling. If you take an atom and put it up beside a surface, then the energy levels of the atom allow the electrons in the surface to kind of leak out through those energy levels into the vacuum. So if you are measuring how much of the electrons get out into the vacuum, if you are right at one of these energy levels of the atom, then in fact you get an enormous enhancement of the tunneling current. This permitted us, in the late '60s and early '70s, to resolve some puzzles that had been brought to my attention by Gert Erlich when I was at the General Electric company of why, when you put certain absorbates on tungsten that, although the work function of the material went up, in point of fact current went up, too. The reason for that, of course, turns out to be this extra current that leaks out through the atomic energy levels. When you energy-analyze the electrons that are emitted, what you discover is that these levels have great big resonances in them. Ward Plummer at that time went to try to find these resonances, which Mike Alferieff and I had predicted. Everybody thought this was a fool's errand. But in point of fact, he did find them and won some awards for that. Not only that, but later this became very popular in photoemission spectroscopy because you see these same bumps when the initial state of the photoelectron is in one of those atomic states. So we used to joke around in the mid-'70s there would be sessions on photoemission and everybody would be showing their bumps. We used to call that "bumpsmanship." Those were very active and interesting times.
The third item that's mentioned in that article is a study of molecular and in particular organic solids. In the late '70s, that was a real frontier. People did not understand very much about the organic solid state. The traditional ideas about band theory and the things that you've come to know and love from your solid-state physics really don't apply to molecular solids because the electron states in these solids are localized, because in most of these materials the disorder is very large.
This has some very important consequences. I used to say that in fact organic semiconductors were not semiconducting organics, when in point of fact, they were localized state organics. You have to understand the consequences of that for the electron transport and for the surface properties and everything else. So there's a lot of body of work reported in that article about how you characterize the electronic states in organic solids. At the time, we applied that work to in fact learn how to get charges through polymer films. In those days, if you shot a charge into a polymer film, it stayed there forever. The only thing that happened is the polymer eventually turned to powder. We wanted to make large-area photoconductors and we had to get charges through these photoconductors in order to do that. There was an experimental program at Xerox at the time, and I was doing the theoretical work. We learned, in fact, how to put dopants in these materials so that you could get charges through them.
The work that I did on the design algorithms for these photoconductors turned out to be very important. It spawned an entire class of Xerox products, the so-called 10-Series products that have generated, certainly, on the order of hundreds of billions of dollars for the Xerox Corporation and for which I was subsequently elected to the National Academy of Engineering.
That's all, I think, that I will try to say about the scientific work that was done during the '70s. In the late '70s in particular, in 1979, I became President of the American Vacuum Society. So I thought that I would take the last few minutes of this interview to tell you a little bit about some of the legacy of that era in the American Vacuum Society.
I think probably the greatest legacy that I leave you, the present members of the American Vacuum Society, really was the bringing of science and in particular surface science to the vacuum technology organization that was here when I arrived. I was always enormously impressed at the good humor and the goodwill of the gentlemen who ran the American Vacuum Society at that time because they entertained nuts like me coming in and setting up all kinds of new programs. Unlike their physicist brethren, who told us we weren't good enough for them, the folks in the American Vacuum Society—of whom I might add Jim Lafferty who is here interviewing me was one—welcomed us with open arms.
In 1971, I organized the First International Conference on Solid Surfaces, which in fact has now become a regular conference. This was an enormous event because we had a lot of Nobel Prize winners coming to the Vacuum Society meeting to give talks. Everybody really felt like this was a great event. I still remember, we had a wonderful reception. I think Mars Hablanian planned that reception at the museum. But this was a really marvelous event. It has, as you know, become a regular event now together with the IUVSTA meetings. That was sort of my introduction into the management, if you will, of the American Vacuum Society.
The second activity that I worked on for the society was really to try to get the American Vacuum Society to become a full member society of the American Institute of Physics. Now, the American Institute of Physics is a society of societies. Basically, it is a collective publishing co-op, so that the member societies get their journals published through the American Institute of Physics. But many prestigious societies belong to the American Institute of Physics, like the American Physical Society, the Optical Society of America. So it was regarded as a very desirable thing by the leadership for the American Vacuum Society for us to become full members. So I had to put together and orchestrate the preparation of the proposal for us to become full members and had to go down and talk to the board and convince them that in point of fact we really, really were a respectable scientific society and worthy of being included in this august body. That basically worked. It didn't work the first time. We made our first try around 1972-73, and there was some confusion there which I subsequently learned a lot more about than I every wanted to know. But in 1976, we had a second try at it and we got in. I served on the board of the American Institute of Physics sporadically from 1976 all the way through 1987. I got to learn a lot about the American Institute of Physics.
I understand from Jim that you wanted some humorous anecdotes. I think probably the most humorous thing that I remember is that in the American Institute of Physics, the American Physical Society really felt they ran the American Institute of Physics. So they were constantly harassing the poor guys who were in fact the executive directors of the American Institute of Physics. Bill Koch was the director during these years, and I sat in these board meetings and watched Bill Koch getting beat up, and I really felt for the poor guy. Poor guy, he's really a very fine gentleman. But it came to a head. I served on the Executive Committee, which is the small subgroup of the board that really runs the American Institute of Physics. Jarius Quinn, who was head of the Optical Society, and I were sort of practical types, and we really resented the fact that the Physical Society constantly beat up on the poor executive director. So at one of our off-site retreats, the American Physical Society said that there was some financial thing that had been not done to their satisfaction by the AIP, and Bill Koch was going to fix this or they were going to pull out. And that was Jaris' and my moment. Jarius and I rammed through a motion past the Executive Committee that said that if the American Physical Society didn't pay their bill within the next 24 hours, they were thrown out. [Laughs] I don't think the American Physical Society has ever recovered from that Executive Committee meeting.
I now serve on the Executive Board of the American Physical Society. So there's a whole new group of people there and a new Executive Director of the American Institute of Physics and I'm happy to tell you that the relationship between those two organizations has greatly improved. But the improvement in the organizations dated from that Executive Committee meeting when the American Physical Society realized that given the choice, they were history.
Well, so much for my exciting adventures with the American Institute of Physics. There were many others. We built a new publishing building at Woodbury. That was an exciting thing, which Lou Branscombe and I managed to get through the board. This was a very conservative group of people and we tried very hard to point out to them how they were going to coin money if they did this. They finally, after great and awful deliberations, finally managed to build this building. And they did indeed coin money once they got it. It's an amazing group of people. That's all I can say.
The third aspect of what I think was the legacy of my era to the American Vacuum Society was in the late '70s when I was President and the early '80s, I really made an enormous point of the fact that the Vacuum Society, although it was now a surface science society as well as a vacuum technology society, the future was clearly in electronics. During those days, each president of the American Vacuum Society got an opportunity to in fact give a talk at the Vacuum Society meeting. So I gave a talk, which is now published [holds up paper] in the Journal of Vacuum Science and Technology called "Frontiers in Microelectronics and Thin Film Components." A basic theme of that talk was that the American Vacuum Society should aspire to become the home of the people who did the process physics associated with the manufacture of semiconductors. We started sponsoring special sessions. There's a table in this paper that describes how many of the activities that were going on in the Vacuum Society were directly pertinent to this industry. And we formed, at that time, the Electronic Materials and Processing Division, whose goal was to marry the scientific expertise evident in a surface science division with device technology and manufacturing technology, which would be resident perhaps elsewhere in the Vacuum Society, which would be necessary in the semiconductor industry.
That, in fact, actually happened. During the course of the ensuing three to five years, the Electronic Materials and Processing Division was formed. It prospered. Most of the recent presidents of the American Vacuum Society have come from the Electronic Materials and Processing Division. We have expanded our interest into the manufacture of semiconductors and have had topical conferences on semiconductor manufacturing. The Journal of Vacuum Science and Technology B is now bigger than the Journal of Vacuum Science and Technology A. And the Vacuum Society has indeed become the premiere society for the presentation and publication of results in the fabrication of semiconductor microelectronics by what we call dry processing.
So all of these things came to pass. In the Vacuum Society as we know it today—of course, Electronic Materials are a major component—but the Vacuum Society of 1980 was a metal physics vacuum society, just like the Vacuum Society of 1970 was a vacuum technology society. So this 20-year period from 1970-1990 really saw two major transformations of the society, each of which rendered its activities more important and more pertinent to the national welfare. In fact, I was very interested to read—to pick up another follow-up—just this past few weeks, for those who are interested in Washington politics, there has been something called the Ehlers Report [shows copy] , which is called Unlocking our Future. This is a report to Congress written by a subcommittee chaired by Vernon Ehlers, which is a testimonial to the value of basic research and the funding of basic research to the American economy. It is based on a prior report [shows report] by the Committee for Economic Development called America's Basic Research: Prosperity through Discovery. I found it truly amazing, when I went and prepared for this interview with you, to go back and read my 1979 Presidential Address and find that, in point of fact, the main points in that address are precisely the same as the main points that you will find in these documents, which constitute the apologia for the support and growth of basic research in the United States in 1998. It is amazing how little times change, although what was a very unpopular and not very interesting point of view in 1980 has become a very popular and desirable point of view in 1998 now that the Cold War has ended and research does not get funded automatically because of support of defense.
I think a fourth element of my legacy to the American Vacuum Society really is associated with the Journal of Vacuum Science and Technology. I see I didn't bring a prop; I had one sitting on my desk. But over the years I served as the Chair of the Publications Committee, and one of the main things that I recall is that in the early '70s as I was working on the publications of the American Vacuum Society, basically when I came into the American Vacuum Society, we used to jokingly refer to the Journal of Vacuum Science and Technology as a comic book. They were very thin little volume, they were stapled together, and the articles in those volumes were little different than the articles in most archival technical journals.
During the course of the '70s, that changed completely. We started putting the publications of the conferences into these journals. We tried to get good review articles in the journal. As I indicated earlier, we expanded the scope of the journal. We got other conference proceedings—this was the era when we went out and started acquiring the PCSI Conference and the Three Beams Conference. So by the time that my association with the journal ended in the early '80s, the Vacuum Society journal was now a very substantive journal with several thousands of pages, issues that were very thick, and authors who were world famous. So this was another major transformation in the Vacuum Society which I and many other people worked very hard on.
I still remember (this was not in my notes, Jim), but I remember one of the two bitter wars of those times. One, how on Earth could we ever make money with this thing? And I finally succeeded in pointing out to people that if, in fact, you did birth control on the pages, you could make a mint. And the second war we had during that era was whether or not we should give it to people on membership. Because everybody said, "Gee, if you give it away, who's going to buy it?" Well, folks, let me tell you the answer. I'm sitting on all the publications committees of the American Institute of Physics. The Journal of Vacuum Science and Technology is one of three journals in the entire American Institute of Physics whose circulation has been growing, not dropping, at 6% a year.
So believe it or not, that group of fine gentlemen who were listening to us nuts tell them that if they gave it away they'd sell more, they actually made a good profit and made good money off of that thing, in spite of what everybody at the time was deathly afraid of. We have wound up with one of the most popular and one of the most best-read journals in all of the AIP stable, which to my enormous personal satisfaction, is on the shelf of each one of you who is in the society. So that information gets to you so that you can use it. It doesn't stay locked up in some damn library which is locked on the weekends and you can't get in. You've got it, you've got it for the price of your membership, and that is a real tribute to the men and women who ran the Vacuum Society in the '70s, because they didn't believe it could happen but they tried it anyway.
That brings me pretty much to the conclusion of what I wanted to share with you today. I wanted to mention one last legacy. Peter Mark was the editor of the Journal of Vacuum Science and Technology when I first became involved with the Vacuum Society. Actually, Frank Probst was at the very beginning, and Peter Mark took over the job from him. Peter and I became very good friends and we wrote a lot of papers together on the surface structure of various II-VI semiconductors—zinc oxide and cadmium sulfide and things of that sort. Peter was the editor of the Journal of Vacuum Science and Technology at the time that I was President. At the beginning of that year, in February of that year, Peter went to the hospital. He had a cough, and he discovered he had lung cancer. By September, he was dead. So John Vossen and I spent considerable effort instituting what is now the Peter Mark Award in Peter's honor, and that is now given to outstanding young men and women each year for outstanding contributions, and people who will later in their careers become contributors like Peter. John Vossen himself died not long after that. So this award, which is the last thing that I wanted to mention, really is the legacy on behalf of Peter and John, actually, although that did not happen in a formal way. Which I think those of us in my generation leave to you.
I guess my closing thought is that when we were on the bridge, we took care of your society. It's your turn now to make sure you do a good job. Thank you.
1 Holds up a copy of History of the Vacuum Science and Technology. Edited by Paul A. Redhead and published by the Education and History Committees of the American Vacuum Society as M-15