Awards > Awardee Interviews > Interview

Interview: Steven George

2017 John A. Thornton Award Recipient
Interviewed by Richard Brundle, November 2017

BRUNDLE:  My name is Dick Brundle.  I’m representing the AVS History Committee, and today we are doing one of the interviews of our major award winners for the Oral History Project.  So today I’m interviewing Professor Steven George from the University of Colorado.  So Steve, would you just say hello so that the transcriber will recognize your voice?
 
GEORGE:  Yes.  Hello.  This is Steve George from the University of Colorado for a voice check.
 
BRUNDLE:  Okay.  So we’ll start off by reading the citation for your award.  Some of them are very long, and this one is very short and precise.  So the award is the John Thornton Memorial Award and Lecture, and the citation reads: “For seminal contributions to understanding, development and applications of atomic layer deposition.”  There was a talk that went with this, but it was given yesterday.  What was the title of that talk?
 
GEORGE:  The title was “Atomic Layer Deposition: Highlights from the Past 25 Years.”
 
BRUNDLE:  Oh, okay.  So an overview of everything since you started.
 
GEORGE:  Exactly.  I started in the area of atomic layer controlled growth about 25 years ago.
 
BRUNDLE:  Okay.  So I’d like to start off with your history—where you were born, maybe a little bit about the family you were in, and then through into high school.  Those things are not mentioned in the write-up here, so let’s start from there and see where it goes.
 
GEORGE:  Well, I was born in eastern Iowa—Anamosa, a town of about 4,000 people.  So I basically grew up in a small town.
 
BRUNDLE:  That’s actually pretty interesting because everybody I’ve interviewed so far—not just today, but for the past—same thing.  They’ve all come from small towns.
 
GEORGE:  Anamosa was small town in agricultural Iowa.  My parents were school teachers.  My dad taught industrial arts and my mom was an elementary school teacher.  She taught first grade.  At school, about half of the people lived in towns and half of the people were from farms.
 
BRUNDLE:  How big was the school?
 
GEORGE:  The school was a consolidated school.  It used to be that all the little small towns had their own schools.  But when I was going to school, they were in the process of consolidating.  So I probably had about 100 in my class.  The Anamosa consolidated school system was drawing from all these other small towns where their schools had collapsed.  My town, Anamosa, was kind of the magnet school.
 
BRUNDLE:  But you didn't have to travel very far, though, because you lived there.
 
GEORGE:  I lived in Anamosa.  But then it turned out to make use of the facilities of all the schools that had closed, I was bused to another town for sixth grade and then another town for seventh grade.  So I was bused around for several years.
 
BRUNDLE:  Okay.  So you're in school there.  I assume by the time you get to high school you have some feelings about what direction you want to go in life.
 
GEORGE:  Yeah.
 
BRUNDLE:  Did you start thinking about science then as a career, or how did that happen?
 
GEORGE:  Oh yes, definitely.  In fact, I started thinking I wanted to be a doctor at about third, fourth grade, so pretty early on.  So that’s what started my interest in chemistry because of thinking I was going to be a doctor.
 
BRUNDLE:  Medical doctor, yes.
 
GEORGE:  Yes, that’s right.  Well, it turns out in a small town you don't really have that many role models, but the doctor is—
 
BRUNDLE:  The doctor is one.
 
GEORGE:  The doctor is somebody everybody puts up on a pedestal, so I think it was kind of natural.  You know, you gravitate to that.
 
BRUNDLE:  So you have an interest in chemistry because of that, and that presumably progresses through high school. 
 
GEORGE:  Yes.
 
BRUNDLE:  But then getting towards the end of high school, you think about going to university.  At that point are you still planning to become a doctor, pre-med?
 
GEORGE:  Yes, and for me it was a little more complicated, too, because in late junior high, early high school I really felt like I wanted to go beyond Iowa.  [Laughter]  You know, because of the small town and… 
 
BRUNDLE:  Too much corn.
 
GEORGE:  Right.  You know, the small town—it gets to you after a while.  It turned out that I knew someone who had left Iowa and gone to prep school on the East Coast.  Then this became something that I also wanted to do.  So I actually spent my senior year at Phillips Exeter Academy in New Hampshire.  I was really kind of an anomaly there, too, because I was a one-year senior.  But I was there because I wanted a new challenge.
 
BRUNDLE:  That’s a reason to go there, but does that also help in terms of when you want to make an application to university?  The fact that you spent this year there was important?
 
GEORGE:  It helped, definitely.  As a matter of fact, I really didn't know what I was going to do next.  But it turned out once I was there, then it was the natural thing to apply to Ivy League schools.  So that’s what happened.  If I’d stayed in Iowa, I probably would have ended up going to Grinnell College or maybe the University of Iowa; I don't know.  But once I was in New Hampshire, everyone was applying to Dartmouth or Williams, all the East Coast schools.
 
BRUNDLE:  Yes.  So you applied and you started in college.  Now I don't know how it works.  Did you have to declare a major immediately or do you have some freedom?
 
GEORGE:  I was an undergrad at Yale.  I started there as a molecular biophysics and biochemistry major because I was still on the medical track.  That was the hardcore science major for pre-meds at Yale.  But then the problem with that was I was with all the most intense pre-meds.  I also discovered that I really didn't like biology that much.  Also, I should add that I took physical chemistry as a freshman.  Physical chemistry just seemed so wonderfully rigorous.  It had fundamental principles and allowed an organization of the world.  That really appealed to me.  So by the end of freshman year, I had switched my major over to chemistry.
 
BRUNDLE:  Okay.  So that exposure to different things in the university environment and finding out what you liked, what you didn't like.  But you switched to chemistry.  You’d given up the idea, then, of being a doctor.  You no longer wanted to do that.
 
GEORGE:  I actually did, yes, and it was partly because of the pre-meds.  [Laughs]. 
 
BRUNDLE:  Yeah.  Lots of people don't become doctors because they can't pass the pre-meds.  [Laughter]  This was a different thing.  You're interested in chemistry, particularly physical chemistry.  Okay.
 
GEORGE:  Yes, that’s right.
 
BRUNDLE:  So how long, then, were you at Yale?
 
GEORGE:  I was there for four years.  And I started getting involved in research right away.  In fact, I started working the second semester of my Freshmen year with James Prestegard in Chemistry.  I did work on model biological membranes because this was a medical-related topic.  The wonderful thing about Yale was that most people at Yale were not science majors.
 
BRUNDLE:  Why was that wonderful?
 
GEORGE:  Well, because there was a good faculty there, and if you wanted to do undergrad research— 
 
BRUNDLE:  Oh, you got opportunity.
 
GEORGE:  Everybody was happy to have you!  I had many excellent opportunities in several groups.  I was able to work in many labs because it turns out that maybe 80% of the undergrads at Yale, something like that, were not science majors.  In fact, I didn't really even realize that until graduation.  When they awarded the B.A. and the B.S. degrees, there were hardly any B.S. degree candidates that stood up!
 
BRUNDLE:  Is that typical there?  Is that still the way?
 
GEORGE:  Well, maybe it’s changed a little bit.  But when I was there, that was definitely the case.  The humanities were the big majors in terms of numbers.
 
BRUNDLE:  Okay.  So now you're out of Iowa.  You’ve had this great opportunity at Yale.  You’ve changed the direction you're going.  You graduated.  What next?
 
GEORGE:  Well, what was really influential for me was the summer after my junior year.  I was part of an NSF REU program at Columbia University.  I was able to be involved and I worked with Dick Zare when he was still at Columbia.
 
BRUNDLE:  Oh!  Okay.
 
GEORGE:  That was just great because he had such a dynamic group.
 
BRUNDLE:  That could also be pretty intimidating.
 
GEORGE:  Yeah.  It was a big group, but there was so much going on.  I just really loved the whole spirit of that lab and all the things that were going on.  And Dick Zare was such an inspirational guy.
 
BRUNDLE:  I met him when he was very young.  I was a student of David Turner’s, at Imperial College, London.  I think maybe my first year.  Molecular photoelectron spectroscopy.  He must have heard about this and he came to visit and came in the lab and started asking us questions.  Mostly I have to say I hadn't the faintest idea what he was talking about!  [Laughter]  So I knew he was so far removed, you know.  It was just, oh, you know, photoelectron spectra—the electron comes off and we can get to the electronic structure of this molecule.  But he had all sorts of complicated questions and we had no answers.  So I realized I didn't know very much at that point.  Yeah.  Okay.  So you worked in that program for how long?
 
GEORGE:  It was just for the summer.
 
BRUNDLE:  For the summer.  Then you have to make a decision to go somewhere?
 
GEORGE:  Right.  During senior year, I applied to graduate schools.  I had gone to the East Coast to explore the world outside of Iowa.  Then for graduate school, I wanted to go to the West Coast.  [Laughs]
 
BRUNDLE:  Get out of the East Coast?
 
GEORGE:  Right.  Well, it was fun.  I kind of felt like I was an East Coast person by that time.  But I still felt that there was another part of the country that I hadn't experienced.  So I targeted Caltech and Berkeley and Stanford for graduate school.
 
BRUNDLE:  Yes, and you ended up at?
 
GEORGE:  At Berkeley.
 
BRUNDLE:  Who was the prof there that you worked with?
 
GEORGE:  Well, it was funny.  I went to Berkeley thinking that I would work with lasers, you know, because that was the Zare lab.
 
BRUNDLE:  Through Dick Zare, mm-hmm [yes].
 
GEORGE:  I’d worked with Steve Colson at Yale as an undergrad during my Junior and Senior years and I really loved lasers.  So I knew I wanted to do something with lasers.  I thought I was going to work with Brad Moore at Berkeley.  But then I met Charles Harris when I was a student visitor.  And he just blew me away.  He was so out there, excited about everything, and so he really got me and got me to Berkeley.
 
BRUNDLE:  Excited you.  And obviously he accepted you.
 
GEORGE:  Right.  Exactly.  [Laughs]
 
BRUNDLE:  So now you were in Berkeley, which is definitely West Coast.
 
GEORGE:  Right.
 
BRUNDLE:  Both the university and the people and the town.  So how long did that take?
 
GEORGE:  I was at Berkeley for five and a half years.  I was doing work in liquids, on vibrational dynamics in liquids.  I probably could have graduated a little sooner.  But it turned out we had some big controversies in the literature about how to interpret the experiments that we were doing.  So I actually ended up staying for another year to do calculations to prove that what we were measuring was really what we were measuring.
 
BRUNDLE:  So nothing to do with surfaces yet.
 
GEORGE:  No.  That’s right, although Charles Harris’s group had some surface science.  They were split.  They were half surface, half ultrafast, picosecond stuff.  Picosecond when I was there and then ultrafast after I left.  [Laughs]  Things kept getting shorter.
 
BRUNDLE:  Faster and faster.
 
GEORGE:  Yeah.  So I definitely saw a lot of good surface work in the Harris group, although it wasn’t what I did.  But it was going on around me.
 
BRUNDLE:  But that interested you?
 
GEORGE:  Yes.
 
BRUNDLE:  I’m trying to get at what then diverted you towards surface work.
 
GEORGE:  Exactly.  Well, with Harris I spent so much time trying to get the laser to work.  It was a passively mode-locked neodymium glass laser, which at the time was state-of-the-art.  When I started it was state-of-the-art, but then by the time I left it was a dinosaur.  [Laughs]  So I learned a lot about lasers.  I learned a lot about how to tune up lasers.  But then by the time I was ready to finish, I thought, “You know what?  It’s time to do something different.”  It was like I could have gone on and done more laser work, but I just wanted to do something really different.
 
BRUNDLE:  Okay.  So you’ve got a thesis that involves all lasers and involves liquids.  So now you're going to go…How did you decide where you wanted to go after that?
 
GEORGE:  Well what I decided was that—I mean I did like the idea of surfaces, and I knew a little bit about it because of Harris’s group.  So I thought, “Okay, I’m going to try to find someone for a post-doc in surface science and someone who might be interested in lasers with surfaces.”  So I wrote to a number of people, and one of the people that I wrote to was Henry Weinberg at Caltech.  Henry was, again, another amazing person.
 
BRUNDLE:  Yes!  Very amazing.
 
GEORGE:  I don't know that he was thinking, “Oh yeah, we’re going to do laser work,” but he didn't say we couldn't do laser work.  [Laughs]
 
BRUNDLE:  My impression of Henry, when he interviews students, he doesn't really care that much what the background is.  He’s going to assess you on what he thinks your potential is.
 
GEORGE:  Exactly.  So that was lucky, you know.  He wasn’t looking for someone who had had a surface science background.
 
BRUNDLE:  That would fit him, yes.
 
GEORGE:  Right, because I certainly didn't, but we hit it off.  Even though we’re very different personalities, we really hit it off.
 
BRUNDLE:  I don't know anybody who has the same personality as Henry!  [Laughter]  So he would be different, yes.
 
GEORGE:  Yeah.
 
BRUNDLE:  So you hit it off and so now you are interested in surface science and I guess all the things Henry’s group is doing.  Is that when you first got involved or knew about the AVS?
 
GEORGE:  You know what?  Not yet. 
 
BRUNDLE:  Not yet.
 
GEORGE:  Not yet.  I think I vaguely knew about the AVS at that time, but I hadn't-- 
 
BRUNDLE:  Because he was involved quite heavily.
 
GEORGE:  He was, yeah, but I didn't—In fact, I can't remember when I first went to an AVS meeting, but I think it wasn’t until after I started in academics.  In fact, I’m nearly certain I didn't go to AVS until after I had started in academics.
 
BRUNDLE:  So during the time you were with Henry, then, were you tied into any other societies and meetings, or you just stayed away from all that?
 
GEORGE:  Well, I went to a couple of ACS meetings, but I wasn’t really involved with AVS at that time.  I was kind of in transition.  I wasn’t quite sure who I was, and when I started with Henry, I was doing temperature-programmed desorption.  It might have turned into electron energy loss spectroscopy because I had a background in vibrational work.  But what I found after being at Caltech in Henry’s group for maybe three or four months is that I really missed the lasers and the dynamic and kinetic aspects.  So I found out also that there was a laser library at UC Berkeley that loaned lasers out to different groups.  I had some ideas for some experiments.  I asked Henry, “Can we apply for this laser to look at surface kinetics?”  I got really interested in the idea of how to measure surface diffusion.
 
BRUNDLE:  Okay.
 
GEORGE:  This was the beginning of the idea of the laser-induced thermal desorption technique for measuring surface diffusion.  So we wrote a proposal, submitted it to the laser library, and got turned down.  [Laughs]  So then okay, I’m back in the lab doing temperature-programmed desorption.  But then I found out about Rich Hall at Exxon in New Jersey.  Actually, Mary Mandich was a post-doc with Jack Beauchamp at Caltech.  She had just been at an ACS meeting and heard Rich Hall talking about laser-induced thermal desorption to look at reaction kinetics.  He was looking at methanol decomposition on nickel, and she said, “You know, he’s set up to do this.” 
So I contacted Rich Hall and I said, “Would you like a post-doc?”  [Laughs]  Actually, I had a Bantrell fellowship from Caltech, so Henry really wasn’t paying me from a grant.  I went to Henry and said, “Henry, if I go to Exxon and work with Rich Hall, maybe I can get some preliminary results so then we can write another proposal to the laser library and maybe get a laser for Caltech,” and he said, “Sure.  That’s great.”

I went to Exxon and worked with Rich Hall.  It was an incredible time because I really knew what I wanted to do and how to model the results and everything.  We were able to get the experiment going and had preliminary data in just a couple months.  It was great because Rich had the setup.  It was all working.  So with that data, then we were able to get a laser.  We rewrote the proposal with the preliminary results and they couldn't turn down the proposal at that point.  We were able to get a Q-switched Nd:YAG laser for surface diffusion experiments at Caltech.  [Laughs]  It is quite an interesting story.
 
BRUNDLE:  Well, and it sounds like you were extremely proactive in getting to where you wanted to be here.
 
GEORGE:  Yeah, that’s right.  But then it turned out the experiments really didn't happen.  I was a little naïve in terms of how much time it was going to take to get all the laser stuff set up for the laser desorption experiment at Caltech.  But I learned a tremendous amount because I put an old chamber together based on parts from the JPL warehouse because Henry didn't have an extra chamber.  I was able to basically scrounge stuff from around Henry’s lab and also from JPL.  I got the basic experiment assembled.  Probably if I’d had more time, I would have gotten some results at Caltech.  But I ran out of time.
 
BRUNDLE:  Yeah.  Okay.  Next step from there, then.
 
GEORGE:  The next step was then academic jobs.  And I didn't actually know what I was going to end up doing.  But Charles Harris called me when I was at Caltech and he said, “You know, Steve, there are quite a few academic jobs this year.  You should apply.”  And I’m going like, “Really?”  [Laughs]  So I applied for jobs and there were a lot of openings that year.  This was really fortunate for me.  I ended up getting a number of offers.  It came down to Bell Labs and Stanford.  That was really tough because there were so many good people at Bell Labs.  I had been there on a visit and John Tully was my host and Mark Cardillo was there.  These were just great people.
 
BRUNDLE:  Yes.  John Tully was there when I was a post-doc there back in ’68 or ’69.
 
GEORGE:  Wow!
 
BRUNDLE:  He had just joined, I think.
 
GEORGE:  Okay, good.  So you know what I mean. 
 
BRUNDLE:  Yes, yes.
 
GEORGE:  It was a tremendous environment.  But I think that in my heart I wanted to be at a university.
 
BRUNDLE:  So you decided on Stanford.
 
GEORGE:  Yes.
 
BRUNDLE:  Okay.  I know I started seeing you and interacting with you and knowing about you then.  I probably met you before, maybe in Henry’s group, but… 
 
GEORGE:  I think it could have been.
 
BRUNDLE:  But I don't really remember that far back, yeah.  [Laughs]  So you must have been involved or started being involved with AVS around that time?
 
GEORGE:  Well, it was a little later.  When I got to Stanford, there was going to be a Dynamics at Surfaces Gordon Conference the following summer.  I thought, “Okay.  You know what?  We’re going to work like hell and we’re going to get some results for the surface diffusion of hydrogen on ruthenium (001)”  I used ruthenium because Henry’s group was big into ruthenium (001).
 
BRUNDLE:  Yes, I remember that.
 
GEORGE:  So we set up and we actually did have preliminary results for hydrogen surface diffusion on ruthenium for that Gordon Conference.  That was summer of ’85.
 
BRUNDLE:  ’85.  Okay.  I never went to the dynamics conference.  I’m sure my colleague Dan Auerbach was there.
 
GEORGE:  Yeah.  I’m sure.
 
BRUNDLE:  Probably Alan Luntz as well.
 
GEORGE:  That’s right.  But actually, thinking back, the first meeting that I went to that was a surface science meeting was actually just before I went to Caltech.  This might be where I met you.  There was a very good meeting at Monterey.  It was called Vibrations at Surfaces.
 
BRUNDLE:  Oh, yes.  Yes.
 
GEORGE:  Yes.  That was the first time I met Yves Chabal.  Henry was there and Dave King— 
 
BRUNDLE:  At the Asilomar conference.
 
GEORGE:  Asilomar, yeah.
 
BRUNDLE:  Yeah.  I was a co-organizer of it with Hans Morawitz, another guy from IBM.
 
GEORGE:  Yes.  Wonderful, wonderful meeting.  Yeah, it was great.  So that was kind of my introduction… 
 
BRUNDLE:  That was your introduction, yeah.
 
GEORGE:  …  to all these people in surface science.  So that was, I think, my first surface surface meeting.  But then I think I applied and went for a talk or a poster at AVS.  It would have been the following fall of ’85, so that could have been my first AVS meeting.
 
BRUNDLE:  And then you obviously got very heavily involved with AVS after that.  But you're not yet doing any ALD work.
 
GEORGE:  No, that’s right.  So I got involved with AVS, mainly with the northern California AVS chapter.
 
BRUNDLE:  Yes, which was very strong then—unfortunately not now.
 
GEORGE:  The northern California chapter was wonderful for the local community.
 
BRUNDLE:  We had organized local meetings in surface science.
 
GEORGE:  Absolutely.  It was great for the students, yeah, and that was when— 
 
BRUNDLE:  Yeah.  That all faded away when people like me left and Bob Madix, and there were a few people who were the organizers.  But yes, it doesn't happen now, unfortunately.
 
GEORGE:  So really the Stanford days were focused on single crystals, surface science, diffusion kinetics, adsorption/desorption, lots of laser desorption work to measure these phenomena.  But no ALD yet.
 
BRUNDLE:  So how did that come about, your first interest in ALD?
 
GEORGE:  Well, I left Stanford at end of ’91 and went to University of Colorado.  I really told myself when I made that move I was going to do something different.
 
BRUNDLE:  So each time you move you're going to do something different and you do!
 
GEORGE:  Right.  I think it was good, although it wasn’t clear where it was all going.  But I’d done a lot of work during the last couple years at Stanford on kinetics on silicon surfaces that was related to silicon processing.  We never really grew a film, but it was all kind of adsorption/desorption, sticking coefficients, that kind of stuff.  I thought, “Wouldn't it be really nice?  We’re so smart; we can measure all these things.  Wouldn't it be great to actually grow a film with some intelligence based on all the kinetics that we’ve figured out?” 
So that’s when I started to think about growing films.  At that time, we had some funding from the Office of Naval Research.  There was a guy there—not my program manager, but someone else who was at ONR, Max Yoder.  He had this initiative—it came out something like ’91, ’92—on how to do atomic layer control of silicon growth.  So I really started thinking about what can you do with surface chemistry to grow films with atomic layer control.  That thinking was stimulated by the ONR program.
 
BRUNDLE:  Okay.  On the other side of the world we’ve got Ritala.  Was he already in it then?
 
GEORGE:  Yes.  That’s right.  He was.  He’s a little younger than I am, but he was a grad student or postdoc with Leskelä at that same time.  But I was going to say - because I gave this talk yesterday - I went back and I tried to reconstruct how it all happened.  I wanted to give the highlights and be historically accurate. But actually, because of the silicon work, I had pretty strong ties with Japan.  I went to lots of meetings in Japan where they were very interested in silicon.  This was in the late ’80s, early ’90s.  Japan was really the place, and then they faded.  But there were a couple people there at the time that I felt were really thinking.  They were on the forefront.  Masataka Hirose—I really liked that guy, and then there was another guy, Yasuhiro Horiike, both at Hiroshima University.  Horiike was a plasma person, and Hirose was very much into deposition of all kinds, a little bit of surface science.  So I applied to NSF for a travel grant to go to Hiroshima.  I spent two summers there—well, just one month each summer—in Hirose’s lab. So when I think about what influenced me first.  Was it the work coming out of Finland or was it the work in Japan?  Really for me it was the work in Japan. There was some beautiful work being done in Japan at that time, and we don't really acknowledge it so much now.
 
BRUNDLE:  No.  I didn't even know that was in the history of ALD.
 
GEORGE:  Yes.  There was Nishizawa, and there were a lot of people at RIKEN Labs, the national lab there.  They were doing beautiful things.  Going to Japan gave me a chance to think about that stuff.  Also Hirose was wonderful and he set up these trips for me to travel around and visit all these other labs.  [Laughs]  So I really got to see Japan and see what was going on.  I think that’s what really got me started on the road of atomic layer control.
 
BRUNDLE:  Yeah.  So once you get into that, let’s see.  When was I at Applied Materials?  I think that we certainly overlap.  Industry starts hearing about this and they’re very, very keen.
 
GEORGE:  Exactly.
 
BRUNDLE:  So did various industries start approaching you to be involved in programs with them?
 
GEORGE:  Not right then, but later.  That was early ’90s.  Mid ’90s, things had kind of reached a minimum.  The Japanese work was coming down because their government wasn’t funding it.  That was also just before the Applied Materials of the world really started to get interested.  But yeah, by the time it got to be 1997, ’98 you could just kind of feel the growth.  That was when I started to talk with companies. 
 
BRUNDLE:  Yeah.  That’s when I was there, from ’97 to 2003.  I could see it growing and see your involvement.  Yes.
 
GEORGE:  We had been working on the ALD of aluminum oxide and some other dielectrics.  The high-k gate problem was huge.  Howard Huff from Sematech had this gate stack workshop.   I went to that workshop many times and that really pulled me into the semiconductor world.
 
BRUNDLE:  Yeah, really into the integrated circuit field.
 
GEORGE:  Yes.
 
BRUNDLE:  So then time goes on and you do that, and now we have, at the other end, which has been around for a while, what is the acronym… ALE?.  How did that come about in your part, the ALE part, the etching part?
 
GEORGE:  Etching stuff, yeah.  The etching came about because of ALD.  I had a student in the lab, Younghee Lee, and he was actually growing a variety of metal fluorides by ALD.  It turned out that one of the metal fluorides he wanted to grow was tin fluoride, so we used Sn(acac)2 and HF.  Younghee figured out how to use HF from a liquid HF source known as HF/pyridine.  This liquid HF source turned out to be what made everything possible. 
Younghee was trying to grow tin fluoride, and of course all of our growth experiments usually started on aluminum oxide because it was the go-to starter surface.  Everybody could do that, so we knew that if we always started with aluminum oxide, people could repeat what we were doing.  So anyway, Younghee was trying to grow tin fluoride on aluminum oxide and lo and behold - he was doing work with the quartz crystal microbalance - instead of seeing the mass go up to grow the fluoride, the mass went down.  But it went down perfectly linearly!  So it looked like ALD, except… 
 
BRUNDLE:  It was in the wrong direction.  [Laughs]
 
GEORGE:  It was the wrong direction, yeah.  So that tipped us off that this etching was occurring.  At first we were really puzzled because we thought, “Well, what is going on?”  [Laughs]  But then after that kind of wore off, we realized that the leads hadn't gotten switched [laughs], we realized that there really was something happening.  And that’s what led us to start to think about how we could be etching the material.  It turned out that the timing of that accidental discovery was perfect.  The semiconductor world didn't really care that much about atomic layer etching until things got so small and started to go into 3D.  So the etching now has gotten a lot of attention.
 
BRUNDLE:  Yeah.  Well, the whole wafer world is deposit, etch, and find ways to do it that result in nanodimension patterning.  [Laughs]
 
GEORGE:  That’s right.
 
BRUNDLE:  So you’ve got the second half now, the etch, going, but there’s something in here that says spatial ALD.  What does that mean?
 
GEORGE:  Spatial ALD, yeah.  In terms of what I’m doing with ALD now…You know, we’re still very active in ALD, but where I think the needs are now for ALD are in commercialization and in scale-up.  Like how to do things faster, with less cost, maybe in a roll-to-roll format.  So spatial ALD is where the substrate moves.  Usually normal ALD is temporal ALD where the precursors come in sequentially and then are removed.  In spatial ALD, it’s the substrate that moves and the precursors flow continuously from definite places in space.  So the substrate comes through and you do the same A-B, A-B sequence of reactions, but you do so by the substrate moving past the precursors.
 
BRUNDLE:  I see.
 
GEORGE:  So that’s spatial ALD, and with spatial ALD, it’s possible to really do ALD much more rapidly, like at least an order of magnitude or more faster.
 
BRUNDLE:  I see.  Yes.  The other thing that sticks out here is this company that you founded, ALD NanoSolutions
 
GEORGE:  Yeah, that started really quite a long time ago, 2001.
 
BRUNDLE:  Yes, I see that.  16 years, so…Is it still going?
 
GEORGE:  It’s still going. 
 
BRUNDLE:  Yeah, and is it fruitful?
 
GEORGE:  It had a slow start.  We didn't take any money from any investors.  It was all self-funded and government SBIR-funded.  We did have one angel investor at the very beginning.  So maybe that was partly why we had a slow start.  But also that was kind of fortunate because we didn't get closed down because we didn't make enough progress in a certain period of time.  ALD NanoSolutions is still going strong.  It turns out it started with ALD on particles, but now it’s ALD on polymers, too.  And there’s a roll-to-roll aspect of what the company is doing.  It’s predominantly ALD on particles.  The company is doing quite well now because we discovered that ALD on the particles that make up electrodes for lithium-ion batteries - if you put just a small amount of material on the surface - it can really enhance their stability.  So it’s been important for capacity stability for batteries.
 
BRUNDLE:  Very important, yes.  Okay.  So that pretty much, I guess, brings us up to date.  Of course you’ve been the past president of AVS.  How long ago was that?  Three years?
 
GEORGE:  A couple years ago, yes.
 
BRUNDLE:  So what’s your role in AVS now?
 
GEORGE:  I did pretty much everything in AVS—trustee, board of directors, president cycle.  But the problem is once you go through the president cycle, you kind of go out to pasture.  [Laughs]  But no, I’m still really involved with the ALD meeting and also with the ALE workshop that just started.
 
BRUNDLE:  Two very successful meetings.
 
GEORGE:  Yeah.  The ALE workshop just started.  Actually, I was just co-chair of that workshop this last summer.  So that’s really the main thing I’m doing right now.
 
BRUNDLE:  So not so much to do with the organizational aspects, but the technical aspects within AVS.
 
GEORGE:  That’s right.
 
BRUNDLE:  Any comments where you think AVS should be going?  Direction?
 
GEORGE:  Well, I think it’s a good news-bad news situation for AVS.  I mean the great thing about AVS is it’s so interdisciplinary.
 
BRUNDLE:  Yeah, that’s what attracted me in the first place when I came.
 
GEORGE:  Yeah.  In fact, ALD didn't really have any home, but hey, AVS was there and opened up and… 
 
BRUNDLE:  Open arms, took you in.  Yes.
 
GEORGE:  Right.  That’s right.  So I think that’s… 
 
BRUNDLE:  It did that with surface science originally as well.  That had no home.
 
GEORGE:  Yeah, that’s right.  But then also it’s a curse because AVS doesn't align with chemistry or physics, so it’s hard for people, if they’re coming from a traditional discipline, to justify going to AVS.  For me, AVS became so much more important than ACS that it’s my meeting every year.  I mean I would never not come to AVS, but people I know in chemistry, they might not come to AVS because they want to… 
 
BRUNDLE:  Well, it’s the same with me.  I resigned from ACS probably three decades ago, but I think if you are in a discipline…If you’re really thinking about your career, it’s easier to get on if you fit into the conferences and get known in the area of your discipline.
 
GEORGE:  Exactly.  That’s right.
 
BRUNDLE:  Right.  And there are a few well-known people who bailed out of the AVS because of that when they realized it.  Went on to very successful careers, but it’s a much bigger organizational thing to be in ACS.
 
GEORGE:  That’s right.
 
BRUNDLE:  But you're sticking with AVS, I hope.  [Laughs]
 
GEORGE:  Right, and I think AVS should hold to their guns.  They need to remember that that’s what makes them unique, even though it is also a weakness in terms of just organization.  But it’s really their strength.  For AVS going forward, they just have to encourage people to bring in these topics that maybe don't have a home in other places.  Like the 2D materials topic is very successful now, and before that there was an energy topic that was very important.
 
BRUNDLE:  Well, I think, as I remember back, electrical-mechanical polishing started in AVS with no home for that.  Certainly in northern California we took them in as a working group, and some people didn't want it.  “What’s that got to do with vacuum?”  Well, nothing, but it’s processing, you know?  It’s the natural home.
 
GEORGE:  That’s right.
 
BRUNDLE:  So yes, I agree.  This is a strong point.
 
GEORGE:  So I think AVS is really structured very ideally, even though you admit that there are weaknesses to the structure.  Like MRS is very topical and you have people coming in and out for topics, but there’s not any continuity.  With AVS, you have the divisions which give you continuity.  There are people in the trenches, and then you have these abilities to bring in new topics, too.  So it’s a little slower to respond than MRS, but it really has a community. 
 
BRUNDLE:  Yes!
 
GEORGE:  So that’s what I love about AVS, too, is that there’s continuity with the community.
 
BRUNDLE:  Yes.  I do, too.  If you looked at transcripts of other interviews, I always ask this towards the end.  You’ve been doing this for a long while.  You are obviously a glutton for work because you’ve managed to achieve all these things and all the administration.  [Laughs]  What advice would you give to some young scientist just starting, maybe starting his Ph.D. right now for the career?  Any particular thing that you would suggest to them?
 
GEORGE:  You know, I got that question, or a related question, yesterday after the talk.  I think the climate right now is really hard for a starting academic person.  Funding is really extremely difficult.  So what I ended up saying is find an application that you’re intrigued by and really become an expert in that application.  Then structure your research and proposals around that application that you're going to make yourself the expert in.  I think that’s really a pretty good recipe for being successful.  I don't think you can rely on just being a smart guy doing fundamental work now.  It’s just… 
 
BRUNDLE:  Too difficult.
 
GEORGE:  Yeah, and NSF just doesn't have the budget.  They certainly would like to think that they could do it.  But their budgets are going down.  In fact, I feel like right now the only way you can really make it is to get some grants from agencies, but then also have strong ties to companies.
 
BRUNDLE:  Okay.  So we’ve been going for about 40 minutes.  The other thing I didn't ask—I asked about your early life and family.  What about now?  Wife?  Children?
 
GEORGE:  Oh, yeah.  My wife is Robin and we have two twin boys that are juniors in high school.
 
BRUNDLE:  Twins!  More work!
 
GEORGE:  [Laughs]  Yeah.  They keep us busy.
 
BRUNDLE:  And you live in Boulder.
 
GEORGE:  Boulder, yeah.
 
BRUNDLE:  In the town?
 
GEORGE:  Yeah.  We’re in east Boulder where houses are still somewhat affordable.  [Laughs]
 
BRUNDLE:  It’s a great town.  I love the place.  I mean I live in Santa Cruz which is also a great place and is on the coast, but if I didn't live there, there are two places.  One would be Santa Fe and the other would be Boulder.  It’s a lovely place, yeah.  So anything further you’d like to say?  If not, we’ll finish at this point.
 
GEORGE:  I think this has been really a good conversation, Dick, so thanks.
 
BRUNDLE:  Congratulations on the award, and I really hope you do stay heavily involved in the AVS in the future and help us along.