Oral History of Walden (Wally) C. Rhines Interviewed by: Douglas Fairbairn Recorded: August 10, 2012 Mountain View, California CHM Reference number: X6589.2013 © 2012 Computer History Museum Oral History of Walden C. Rhines Fairbairn: Alright we’re here at the Computer History Museum, it’s August 10th, 2012. My name is Doug Fairbairn, and we’re here to interview Wally Rhines, who is the CEO and Chairman of Mentor Graphics, Corporation. Wally has a rich background in both semiconductors and electronic design automation and we want to try to cover both elements of that career in this oral history. So welcome, Wally, glad to have you with us. Rhines: Glad to be here, Doug. Fairbairn: So Wally, we want to start at the beginning, we want to talk about where you grew up, what it was like growing up, a little bit about your family life and especially how that might have influenced your career in technology. So just start off, where were you born? How did it all start? Rhines: I was born in Pittsburgh, Pennsylvania in 1946. My father was a professor at what was then Carnegie Tech and he was an engineer by training, a chemical engineer and later a metallurgical engineer and his father was an architect and so had a long history of engineering architecture and things like that, and when I was 10 or 11 years old, we moved to Gainesville, Florida where my father started the Material Science and Engineering Department at the University of Florida, which today is the largest in the US and so my recollections of childhood are heavily weighted toward Florida; going to junior high school and high school there, and most of my exposure to technology was associated with all the things you do at that age, science fairs and projects tied into the University of Florida so there was a lot of engineering influence all along. <crew talk> Fairbairn: So it came time, you had an interest in science; you figured that was going to be a career path in one way or another, is that right? Rhines: So I wasn’t that confident of directions when I was in high school. I liked science, math, but I also liked languages, literature, a variety of things so it wasn’t so clear. But I had a father who was very engineering oriented; He would ask me what I wanted to do. If I said, well I might like to be a lawyer, he would say, well, engineering is an excellent preparation for law school. Or if I said, well, I think maybe being a doctor might be interesting. He would say, well an engineering undergraduate degree is a terrific way to get started in medicine and so pretty soon I figured out what the message was. Fairbairn: You did have an influence. CHM Ref: X6589.2013 © 2012 Computer History Museum Page 2 of 36 Oral History of Walden C. Rhines Rhines: He did have an influence and we traveled the country looking at universities and he influenced that too. He decided that the University of Michigan had the best undergraduate practical engineering education in the country and so, although I didn't really have a good feel about what I would like, and at that time I could get into virtually any university, I went along with it and so I went to the University of Michigan and... Fairbairn: So had he gone there as well? Rhines: As it turns out, he had gone there, although that didn't seem to influence him so much as the actual program, but we went to each of the schools, met with the professors; of course he knew a lot of the people and for a while he was pushing Illinois and ultimately the only one he vetoed was MIT because he felt all his friends at MIT didn't spend enough time with undergraduates and he was looking for an undergraduate experience, so that's why he thought Michigan was the best <inaudible>. <overlapping conversation> Fairbairn: What about the west coast? What about Stanford? Rhines: So he viewed Stanford as too theoretical; he thought U.C. Berkeley was terrific and in fact when it came time for graduate school, I only applied at Berkeley and Stanford and I got into both with fellowships. He felt that my decision to go to Stanford was a mistake— I could have gone to Berkeley; he felt Berkeley was the premier place and going to Stanford I was going to end up a scientist and maybe not employable. Fairbairn: So stepping back; you went to the University of Michigan, the engineering school there and what was your major? Rhines: My original major was chemical engineering but I graduated with a specialization in metallurgical engineering. Fairbairn: So not electronics, not computers or anything like that. Rhines: Not at Michigan, but when I went to Stanford as a graduate student, I became interested in solid state electronics, because that's what was happening in the Bay Area and an interesting person from the industry, Craig Barrett was a young professor there and his research and career had all been metallurgical engineering, high temperature creep, jet engine alloys, all that kind of thing; he was a metallurgist and Craig was the youngest professor so he spent time with the grad students and we went CHM Ref: X6589.2013 © 2012 Computer History Museum Page 3 of 36 Oral History of Walden C. Rhines out and drank beer and so, as it came time to choose an area of research, Craig was interested in getting into electronics and the only electronics exposure he had had was one student who did mechanical properties of silicon. So I was the first that actually did anything in electronics and I had Gerald Pearson on my committee as well with Craig; Gerald was one of the original transistor group at Bell Labs and Dave Stevenson served as Principal Advisor. And so I did my thesis like so many others in electronics history, on gallium arsenide and it was enough of an exposure for Craig that he moved in the electronics direction and enough exposure for me that I did too. Fairbairn: So what years were you at Stanford? Rhines: I started at Stanford in the fall of ’68 and I completed my PhD in October of ’72. Fairbairn: And so you went directly from Michigan to Stanford? Rhines: I did but it was a very troubled period in the United States; the Vietnam War was at it’s peak and in February of my senior year in college, President Johnson decided that there would no longer be deferments for graduate students, so I had to find a path. I’d already been accepted in graduate school and I ended up getting into a program that was really designed for students coming from junior colleges to get into ROTC in their junior years, but graduate students could apply as well and they favored engineers over lawyers and other majors and so I ended up going in the military the summer of my senior year, going to Fort Benning, going through basic training, and then going into the two year ROTC program at Stanford and ultimately being commissioned at Stanford as a grad student and then having an obligation after that. Fairbairn: So you graduated in ’72, you got your PhD in gallium arsenide; what aspect of that... Rhines: So I dealt with light emitting diodes; my thesis was on precipitation that occurred during zinc diffusion in gallium arsenide but I shared an office with Herb Maruska and he was doing gallium nitride; we were all in three-fives and so one afternoon, we were sitting around in the office speculating about what had not been done in gallium nitride and we got a periodic table out and we started going down all the doping elements and Herb knew results for most of them and we looked up others for what had emitted what kind of light and we came to magnesium and we couldn't find anything on it and Herb said, “I don’t think anyone has ever doped gallium nitride with magnesium”, so Herb went in the lab and did it and made a light emitting diode and low and behold, there was blue, actually blue-violet, light and that was in fact the first magnesium doped gallium nitride light emitting diode and today all the blue LEDs, all the future of lighting, is all based on magnesium doped gallium nitride, so we got a patent. We have a patent that issued in 1974. It was actually a p/semi-insulator “diode”— we couldn't make N-Type gallium arsenide so it was a P-Type with semi-insulating GaN on the substrate for the emission and later people CHM Ref: X6589.2013 © 2012 Computer History Museum Page 4 of 36 Oral History of Walden C. Rhines figured out how to make PN junctions that were much more efficient but anyway, that's where blue light came from in LEDs. Fairbairn: And you were just looking for new things to do, <laughs> you didn't have any particular application or even— I mean had you predicted the blue light would come out? I mean was that your...? Rhines: We had not. Fairbairn: <Laughs>. Rhines: Herb had a lot of experience in gallium nitride. He’d worked for Jacques Pankove at RCA and they had produced blue light with up-converters or down-converters but they’d never found anything that had intrinsic emission down in that range in the spectrum.