Interview: Marjorie Olmstead
1994 Peter Mark Memorial Award Recipient
October 1994
CHAMBERS: My name is Scott Chambers, and I’m from Pacific Northwest Laboratory, and it’s my pleasure to interview Marjorie Olmstead, who is the Professor of Physics at the University of Washington and the winner of the 1994 Peter Mark Award of the Society.
Marjorie, how did you happen to get into the field that ultimately led to this work that you’re being awarded for?
OLMSTEAD: Well, I guess I’ve always known that I was interested in science and that’s what I wanted to go into. When I was first in college, I was sure I was going to go into nuclear physics, and then I had this great awakening my Junior year when I took nuclear physics and discovered that things that were that little should not be that complicated. I was then privileged to have a summer job at Bell Laboratories in the summer after my junior year. They had a special summer research program for women and minorities, which was primarily to get people like me convinced that the job we eventually wanted to have we needed a Ph.D. for. And that summer, I looked at oxidation of gallium arsenide, looking at the problems of putting a different kind of an insulator on top of a semiconductor, and now that’s what I’ve come back to. I’ve gone through clean surfaces and absorbate-covered surfaces, in between; but once again, I’m now looking at the process of interface formation when you try to put two materials that are quite different from each other, an insulator, for example, an ionic material on top of a covalent one.
CHAMBERS: Now you started off your career in industry and then you eventually moved into academia. What caused you to want to make that switch?
OLMSTEAD: I’ve probably been interested in teaching even longer than I’ve been interested in science. I always wanted to teach. When I was in junior high, I wanted to teach junior high, and by the time I got to graduate school, I wanted to teach at the graduate level. I actually applied for a job at Berkeley before I ever went to Xerox, and I knew while I was at Xerox, which was in 1985 and 1986, that I was very interested in going back, and although I had a permanent job there, I sort of played like a post-doc, knowing that I was leaving in a year. And I was privileged there to work with Ross Bringans and Bob Bachrach, who did very interesting work and got me involved in this interface studies. But I think in any job these days, you spend about 50 percent of your time keeping the institution running in return for getting to play in the laboratory. I decided that I really preferred to spend that time working with students, as opposed to trouble-shooting development problems.
CHAMBERS: Now the nature of the work that you’re awarded for has potentially some very important technological spin-offs. Could you talk about the project a little bit and then how it might play into technology in the future?
OLMSTEAD: My main interest is in looking at these interfaces between dissimilar materials. Right now, device technology is limited by the ability to take arbitrary material A and put it on an atomic scale next to arbitrary material B. And what we’re studying is the basic physics of those interactions: What kind of things do you need to take into account when you’re trying to put two materials together? Are there numbers you can just look up in the CRC handbook that will predict things, or do you have to actually make a separate experiment with each different kind of material or each class of material. And one possible application of the particular system I’ve been looking at for the last five or six years, which is calcium fluoride growth on silicon, is as an insulating buffer layer. Right now, primary silicon technology uses an amorphous film, silicon dioxide, which is wonderful. It has very few defects and works very well in integrated circuits. But it’s amorphous, so if we want to expand into a three-dimensional crystalline structure, the hope of putting an ionic insulator, which is lattice-matched to the semiconductor substrate is a very good possibility for these devices. In fact, one application of this system is in infrared detectors. It turns out that lead selenide and lead sulfide actually grow better on these ionic fluorides than they do on almost any other substrate, including themselves.
CHAMBERS: At this point, do you tend to stick with the fluoride on silicon system and do further work on it, or do you feel like the chapter’s pretty much written on that subject?
OLMSTEAD: Well, the process of putting calcium fluoride on silicon, I think we’ve reached a very good and complete understanding of. We now have a map of the kinetic parameters that determine the mode of growth and have we have ways now to grow flat, uniform films. And so our next interest in this particular system is to go on and put something else on top of these fluorides. In particular, we’re interested in trying to make silicon either quantum wells, quantum wires, or quantum dots, depending on how the material wants to go down. If it goes down as islands, we will bury them and have quantum dots. If it’s the steps that nucleate that material, we’ll have wires, and if we’re lucky, we’ll get a quantum well, which we can then explore. To some extent, these insulators, crystalline insulators, are like lattice-matched vacuum, as far as the electrons are concerned. We have band offsets that are as big as a work function. And so we have electrons that can be confined to the semiconductors on a very small scale and yet not have to worry about surface reconstruction and other phenomenon that can complicate trying to figure out what’s going on in an ultra-thin film.
CHAMBERS: Have you tried the silicon overgrowth yet?
OLMSTEAD: We’ve done some preliminary experiments that have showed us that in the process of putting the silicon on top of a fairly thick layer of calcium fluoride, we actually change the initial interface. And so the last six months or so, we’ve been trying to understand that process. At the University of Washington, we’ve just moved into a brand-new physics building, and we’re still in the process of getting the equipment working after the move. Hopefully by Christmas we’ll be back and once again doing these experiments.
CHAMBERS: I know you’ve been quite a champion of the cause of women and science, and you’ve spoken around the state of Washington on the subject. How do you feel that’s going at this point, in terms of seeing more and more women getting into the field?
OLMSTEAD: It’s hard to say. Physics is a very hard job market at this point, and you often wonder how many more people do you want to convince to become physicists. But I think it’s very important that we try and have the people who go on in this field to be people who are very interested in it, and that everyone who is interested in it should have access to it. My goal at the time, when women will have reached equality in this field is when a question like you’ve just asked me, it becomes just as relevant to say, “What’s it like to be a man as a physicist?” as much as, “What’s it like to be a woman as a physicist?” And I really look forward to that time.
There are both advantages and disadvantages. People recognize you, which can be intimidating for a young woman; that if you make a mistake, you’re sure people will remember you. You’re not just that 25-year-old bearded guy over in the corner, that if you’ve made a mistake they may not remember you. But then again, it’s also worked in my favor in that way, too, in that people when they see you, they recognize you. And as I said earlier, also the special program at Bell Labs made a big difference in giving me the self-confidence that I needed early on. I’m a firm believer that self-confidence and self-esteem is probably the biggest predictor of success in a student, male or female. When I get a new graduate student, that’s what I look for.
CHAMBERS: In your working with undergraduates, do you find more and more women that are more gung-ho about physics coming in, as time goes on? I’ve read that the numbers are typically kind of low, and that they just come in and don’t want to study it. But are you seeing any changes there?
OLMSTEAD: Not yet. The fraction of women getting PhDs has been steady, at about 10 percent for probably the last 10 years that I’m aware of. The number of women getting bachelor’s degrees is a little bit higher. I don’t have current statistics, but our own department is somewhere between 15 and 20 percent for the bachelor’s degrees. The University of Washington has a very large undergraduate physics program and there are years when we graduate more total women than any other place in the country, sometimes even including Bryn Mawr, and that we tend to have 40 or 50 majors total a year. And so if 20 percent are women, we might have as many as 10 or 15 women. I think one reason for that is that we encourage physics as a liberal arts degree in addition to physics as a preparation for graduate school, and I firmly believe that we need more technically literate scientists who can also be journalists or lawyers working in environmental chemistry, and so forth. Physics is a very good training for that kind of work.
CHAMBERS: Well, changing the subject once again, how do you think the AVS is doing, in terms of trying to assess its future direction? And as one who’s worked in both industry and academia, do you think there are specific things that the AVS ought to be thinking about that would optimize its future performance in the grander scheme of things?
OLMSTEAD: Well, one thing I’ve really appreciated about the Vacuum Society is that the work that you all do is very interdisciplinary. I trained as a physicist and I approach this from a physics point of view, but I have many friends and colleagues who do very similar work who were trained as chemists, as materials scientists, as chemical engineers. And we all have our own individual societies where we go to meetings, but this is one of the few places where we all can come together and discuss our common problems, and once we learn how to convert from kilojoules per mole into electron volts per atom, then the chemical physicist and the physical chemist can really talk to each other and make progress.
As far as the future is concerned, the balance between technology and the university is very important. For me to bring students to this meeting where they can find out not only about academic jobs, but also talk to people in the equipment manufacturing and so forth industries, only one out of six of PhDs coming out is going to be able to get a job like mine at a research university, and I believe you need to do a lot more to help those other 80 percent of the students whom we’re training to get jobs. And those of us at the University know how to get a university job and we really need the help from the people from the national labs and from industry that we meet these meetings to help our students.
CHAMBERS: Anything else that you’d like to discuss?
OLMSTEAD: No, I don’t think so. I’d like to thank you very much for volunteering at the last minute to do this.
CHAMBERS: Well, it’s my pleasure and congratulations on your award. I think it’s well deserved.
OLMSTEAD: Thank you.