Sensor History

Author: Dennis Dauenhauer


There are certain stories I tend to tell when we have visitors in Sunnyvale or when I first meet people in the sensor business. The extent and detail of these stories vary as is appropriate with the interests of our visitors or the occasion. I like to recount some of the history of silicon based sensors in Silicon Valley and give some examples of applications we've worked on in the past. Often this triggers some common ground upon which we might have interests, people, or other experiences in common to share. I shall try to share some of this by way of this news letter.


The Fairchild Semiconductor Days

For all practical purposes I've been directly involved with the first silicon sensor work in Silicon Valley. The person most responsible for bringing sensor technology to the area was Art Zias. Art was a technical writer at Bell Labs while an engineering student in the late fifties. The physics of piezoresistance in silicon and germanium was derived from the work of Phann, Thurston, and Smith at Bell and was chronicled by Art. Art also worked as a professional saxophone player at the major New York studios during the fifties. In his own words, "I was skilled enough to play with the top jazz artists, but not talented enough to be ranked with them." Pfann's work inspired Art to make a lifelong career of silicon sensors. Bill Pfann made a comment at the time that not only inspired Art, but perhaps defined the industry, "Now that we've studied the transduction effects in semiconductors for the purpose of getting rid of them, maybe they're useful."


In 1960, Art joined GE where he won a competition against Honeywell for an Airforce (WADC) contract on solid state motion transduction. That motivated Tony Kurtz to leave Honeywell and found Kulite. In 1964, Art joined Honeywell to start the Solid State Electronics Center (SSEC). During the sixties, Art lead SSEC's development of piezoresistive accelerometers and pressure sensors for the Aerospace, Industrial, and Microswitch divisions. Hans Keller was then a physicist at SSEC. He later founded Keller Druckmestechnik in Switzerland. In 1969, Art joined ex-Honeyweller, Don Lynam, as director of Engineering at Fairchild Camera & Instrument's Transducer operation. Gene Burk soon left Honeywell to join Art. Art credits Gene with the original work on bulk silicon micromachining. Prior to Gene's work sensors did not incorporate three dimensional structures, only planar structures. Don, Art, and Gene Burk left Fairchild and founded IC Transducers (now Foxboro ICT) with Fairchild's blessings in 1971.


In 1972, Art and Bill Hare founded National Semiconductor's transducer operation without Fairchild's blessings. In addition to ICT, an effort continued at Fairchild aimed at automotive applications. At Fairchild the hope was to develop a manifold absolute pressure sensor, similar in technology to the ignition module, based on silicon piezoresistance technology. With Art's departure, the effort was stopped. National and Fairchild became involved in a legal dispute over the nature of Art's departure. What remained of the technology at Fairchild was sold to Bob Hood, became Cognition, and was eventually sold to Emerson Electric, never to be heard of again.


I met Art in 1973 at a golf outing arranged by a mutual friend and fellow engineer at Fairchild Semiconductor, Rick Schaffzin. Rick became president of IC Sensors in the eighties. Art has a horrible golf swing. It's best that one just learning the game look away when Art swings to avoid the Methuselah curse. Rumor has it that seeing Art's swing may turn one into a pillar of salt.


At Fairchild, we developed the first solid state ignition modules with Delco Electronics, shipping 50,000 modules a week during peak production. I was a process and product engineer for automotive and other hybrid products. The engineering manager was Rodney Smith, now president of Altera.


The National Semiconductor Days

In the early seventies the only commercial silicon based sensor work in the Valley was Art's work (just starting at National Semiconductor), Don Lynam at IC Transducers (also just starting), and the effort at Fairchild (coming to a close through Cognition). Elsewhere in the world, there were other commercial efforts with the work continuing at Honeywell Microswitch, Hans Keller at Keller in Switzerland, Kulite in New Jersey, and at Phillips in Europe. The largest research efforts were at the universities in the United States. There were significant efforts at Case Western, under Dr. When Ko, Stanford under Dr. Kendall Wise, and by John Gragg at Carnegie Mellon. National Semiconductor wanted to get into the business because of the potential automotive applications. Art was asked by National's management to explain "transduction." Art told them he would put it into the simplest terms, and one they could relate to best. He described transduction as the ability to take silicon and convert it to money. That appealed to National, Art was hired and the ten year transducer effort at National was to begin. Art has more accurately described the circumstances, as the events surrounding this statement also provide an insight into the character of National Semiconductor at the time.


In the mid seventies, I assumed responsibilities for marketing of all National's hybrid products, including Transducers. At the time there was a major effort by the car companies to develop an automotive MAP sensor. At National we worked with Delco Electronics and Ford to codevelop two types of MAP sensors. The Delco version had a sensor die similar to the Honeywell sensor die of the time and was packaged in a housing similar to the Fairchild ignition module. This product and versions of it are still manufactured by Delco and other aftermarket suppliers. Similar versions of this sensor were developed for all other major car companies in the world and its specification is the defacto industry standard. The Ford version was a silicon variable capacitance pressure sensor. It is still manufactured today by both Ford and Motorola. However, it is not used by any other car manufacturer. It is more costly than the piezoresitive version. There are other thick film hybrid MAP sensors also serving this market.


In 1977 I was participating in a Transducer Range Commanders conference in Seattle along with Joe Mallon, vice president of engineering at Kulite. At this time Joe had a ton of patents for silicon piezoresistive pressure sensor processing (In 1983 Joe, Kurt Peterson and Janusz Bryzek were to become cofounders of Novasensors; more on them later). I got to know Joe from this meeting and found him to be the most knowledgeable person at that time concerning temperature effects due to semiconductor processing for pressure sensors in silicon. Even today most companies reference his original work for determining appropriate concentration levels for dopants in silicon to set the temperature coefficient of resistance and sensitivity.


In 1978 I was attending Semicon West in San Francisco and was at "Herr Doktor" Janusz Bryzek's presentation on discrete temperature compensation of silicon pressure sensors. Janusz presented a circuit that had at least twenty amplifiers, and several hundred resistors and many potentiometers. The most elaborate scheme for temperature compensation I had ever seen, truly a technical wonder to behold. He was asked by a member of the audience, "Doktor Bryzek what is the error in such a compensation with so many components?" Without hesitation Janusz replied, "there is no error, it.... is perfect!" At the time I felt he could quite possibly be right but wondered how he would test it (An engineers mentality, not a marketing mentality). From this conference I got to know Janusz.


During this same time period American Hospital Supply approached National for a $5.00 disposable blood pressure sensor. The first work started then for what is today, most probably, the second largest pressure sensor application in the world behind the automotive MAP sensor.


The 1977 National Semiconductors Transducer Handbook became the reference book in the transducer business. Most sections of this book are still reprinted with each reprint of the Sensym handbook. This handbook is still the reference book of choice for pressure sensors. The 1977 handbook was unique because each section had an unusual introductory title and preface including, "The pig who squealed Dixie," a section concerning acoustic measurements and "Samson and Delightful," a section on signal conditioning. This book was the result of a years work by Art, Ray Pitts a Ph.D. in physics who was consulting and rewriting the bible at this time, and myself. Ray was the major contributor. He had an unhappy ending to his story at National and a tragic ending to his life shortly thereafter.


In 1980 I became Director of Operations for Transducer Products at National and Art Zias reported to me. It was a truly challenging and joyful time period for us all as Art kept everyone on their toes and entertained. In addition to engineering, Art performed as master of ceremony at the National Semiconductor annual sales meeting and would use me as a sounding board for many of his anecdotes. One of his more memorable ones was about Charley Sporck, founder and CEO of National Semiconductor. In reaction to financial analysts criticism of him at the time, Charley made the statement, "he would chomp on groins and spit testicles." Art, in reference to this statement told an audience of several hundred National employees and sales Reps, "that it just goes to show you that angry rich men can develop strange gourmet fetishes." The charter for the transducer business was to determine what was needed to grow the business to $100 million in a short time period. At the time I didn't know it, but the only other alternative was to exit the business.


National Semiconductor notable persons involved with the Transducer operations.

Most notable was Mike Scott, director of operations for hybrid and transducer products from 1974 to roughly 1979. I reported to Mike during this time period, and he was the most knowledgeable marketing, and possibly the brightest person I have ever met. Mike, who previously worked for Mike Markula at Fairchild, left National to become the first president of Apple Computer and left Apple in 1983 when he and Steve Jobs did not see things the same. Markula, Chairman of the Board for Apple, opted for Steve instead of Mike. Mike left Apple at this time with his eight million shares of Apple stock and has enjoyed himself ever since. He did have one fling in the satellite launching business with the failed launch of their first satellite, and company, Starstruck. The concept for their satellite had considerable technical appeal. But in the end, they had an expensive boat ride that saw their satellite and investment forever disappear into the depths of the Pacific Ocean. Floyd Kvamme was Vice President of marketing and sales for National. Pierre Lamond headed R&D. Both Floyd and Pierre are very well known today in the venture capital community. At National our semiconductor fab processing was done in the linear group, headed by Bob Swanson. Bob left National with a team of National linear people and started Linear Technology, a very profitable semiconductor company today. Their leaving National caused Charley Sporck to file legal action against the group as it "appeared" unusual to see them talking daily in the cafeteria for some time prior to leaving. Especially since they had never socialized before this time. One of the cofounders of Linear, Brent Welling for whom I worked for a brief time period at National, would later join us at Sensym as Vice President of marketing and sales.


At National I was a member of their eleemosynary committee and had the opportunity to visit a sensor group at Stanford University. Kendall Wise was head of the effort and was just leaving to form a sensor research effort at the University of Michigan. I met Jim Knutti who was involved with an implanted integrated injection logic, combination pressure, and temperature sensor used to monitor bodily functions of sheep, funded by the National Institute of Health. Jim worked with Dr. Henry Allen and the two of them later (1984?) started a company to manufacture force sensors using silicon for what Art had earlier published as "the fingertips of the robot." This company, Transensory Devices Inc, was acquired by IC Sensors and Jim and Henry stayed with IC Sensors. Jim left a short time after the acquisition and started a sensor operation in Switzerland with Ascom. Ascom was eventually sold, there was a fire in their fab, and finally they exited this business. Henry joined Jim and the work done with Ascom allowed the two of them to start Silicon Microstructures in 1992. SMI was acquired by Exar in 1995 and Jim and Henry continue to be active at SMI/Exar. They have done some very good work with silicon stress concentration, modeling thereof, and silicon structures for low pressure devices and accelerometers.


The Sensym Days

In 1982 after I made a presentation to National management stating it was not realistic to expect the Transducer business to become at $100 million business in the foreseeable future I was instructed to sell the business. At the time John Nesheim was treasurer for National and provided guidance for me during this process. John later formed Ministry Management with Art Linkletter, of television fame, and has written several books concerning venture capital financing. At that time my marketing manager was Manny Naik, now the president of Integrated Sensor Solutions. Manny and I talked with Joe Mallon and the three of us considered how we might get into the business ourselves. We decided to invite Janusz Bryzek into the discussions as well. After many meetings suffice it to say that we could not agree on a structure for the company the ("Office of the President" later adopted at Novasensors, did not appeal to me) and I decided to propose a leveraged buyout of National's operation and Janusz would join us as Vice President of Engineering.


Manny stayed at National, later to leave and found Integrated Sensor Solutions. ISS is now active in pressure sensors for automotive applications and has strategic relationships with companies in Japan, Germany and Breed Automotive in the United States. Manny is, without doubt, the best marketing person in the pressure sensor business. I was given one month by National to arrange financing for the purchase of the Transducer Group.


Through John Nesheim's referral I was able to arrange quick financing from Robertson, Coleman and Stephen's, now Robertson, Stephens & Company in San Francisco through Bob Cummings. Bob also got Crosspoint Investments to contribute and we developed a business plan with the help of John Mumford, general partner for Crosspoint. I was very lucky to have John Nesheim's referral and introduction to the legitimate financial community. We completed the purchase of the business in October 1982, from this Sensym was born. I had a very good relationship for the prior five years with our European marketing manager in Germany, Helmut Gutgesell. He offered to start a company in Germany with mutual exclusivity for the Sensym products. Thus was born Sensortechnics GmbH. Sensortechnics is today one of the more successful value added suppliers of pressure sensors in Europe.


I located Sensym at 1253 Reamwood Avenue, Sunnyvale, a facility that had been recently vacated by Interdesign. Interdesign had been sold to Ferranti and they moved to Scotts Valley. This address may look familiar as it is where I currently reside with Data Instruments ASG. We put in a four inch semiconductor fabrication facility and had the capability to build linear IC's as well as silicon micromachined structures. Some of our notable work at Sensym included disposable blood pressure sensors for both invasive and non invasive application, including catheter tipped disposable pressure sensors for multilumen catheters down to a size of four french (less than 0.023" wide). We developed a hybrid module for Michelin including a pressure and temperature sensor with a full custom IC (all of which was manufactured in house). The initial use was for tire pressure sensing on the BMW model 850. We developed a full custom artillery shell distance sensor for safe and arm electronics. This included our first silicon accelerometer. The module performed a double integration of acceleration to determine distance. We also developed the first, low cost digital tire pressure gauge. It was, by far, the most sophisticated pressure sensor of its time for the price. The tire pressure business was a business, within a business and had a story of its own. In the eighties Sensym was where a significant portion of the industry research (more correctly, development) was being done. Novasensors did research, Sensym did development.


Janusz Bryzek stayed with us for about three months and left to join Don Lynam who had just left Foxboro ICT to start IC Sensors. In his stead we hired John Gragg from Motorola to manage our engineering efforts. John had worked at Carnegie Mellon on shear strain in silicon for the purpose of manufacturing pressure sensors. This technology had its roots at the Bell Labs in the work of Pfann and Thurston. Three basic technologies are used to manufacture silicon based pressure sensors; variable capacitance, uniaxial longitudinal and transverse strain piezoresistance and shear strain piezoresistance. There are tradeoffs for each rendering one more suitable than the other for particular applications. John and Carl Derrington had been instrumental in taking this technology from the university and commercializing it at Motorola. Motorola is the only company to employ both piezoresistance and variable capacitance pressure sensing technologies commercially. Motorola is currently the only United States non captive supplier of OEM automotive pressure sensors. John stayed with Sensym less than a year. His wife didn't want to live with his commute from Phoenix to San Jose and would not move from their home in Phoenix. John returned to Motorola to pursue interests in another Motorola technology.


Automotive applications have been the catalyst for much of the silicon sensor development. It first started with the manifold absolute pressure sensor and more recently has extended to air bag crash sensors and fuel vapor sensing and has been considered for oil pressure, comfort seat bladders in memory seats, air conditioning pressure switches, tire pressure, and intelligent shock absorbers (Not to mention all the off-road vehicle and truck applications). Research efforts have been funded in Germany by Siemens and Fraunhauffer Institute. Siemens acquired the Bendix sensor research group when Bendix's automotive business was acquired by Siemens. This group had received over fifty million dollars in funding when part of Bendix. The research efforts in Germany have been largely funded by the government (over several hundred million dollars) and the auto industry.


In spite of all this funding the only company that sold products was one small operation near Munich owned and operated by Texas Instrument manufacturing, only piezoresistive sensors for disposable blood pressure. This business ended several years ago.


In 1989, seven years after having taken money from the venture capital folks, as is common in the venture business it was time for Sensym to provide a return on their investment. At Sensym we raised money one other time, in 1984, when a note due National secured by my house was due and I did not have the funds to pay it. To make a long story short, National voided the note and took an equity position in Sensym thanks to Charley Sporck and Gary Arnold, Nationals Vice President of Finance at the time and current member of National Semiconductor's Board of Directors. In 1989 I retained Bob Harris of Kahn & Harris, now Harris-Roja, for the purpose of selling Sensym. We received much interest from a large number of companies interested in acquiring Sensym. After close to twenty visits we had a short list of less than five companies based upon their management compatibility and the price they would be willing to pay. In the end we opted to accept an offer from Hawker Siddeley. Our investors received between seven and ten times their original investment as a return on their investment. The return on investment was acceptable.


Hawker Siddeley had a large sensor group in the United States managed by Dale Bennett in Rhode Island called Fasco Sensors and Controls. This group included Fasco in North Carolina, Elmwood Sensors in Rhode Island, Aerospace and Aviation Inc in Long Island, Mason in Southern California, Laserdata in Florida, Clairostat in New England, and Senisys a fiber optic module company in Texas. I would become very familiar with all these companies through group meetings and when I was asked to provide technical assessment for each of them. We hired Art Zias to consult for us for a year and to provide a technical inventory of each of the Fasco businesses. In 1981 Hawker Siddeley attempted to fend off a hostile takeover by BTR, another British conglomerate. During that time period we came close to being able to repurchase Sensym from Hawker Siddeley but the deal didn't get done before BTR acquired control of Hawker and therefore of Sensym. BTR has a management philosophy totally different from what had been the norm for Hawker Siddeley. BTR has been very successful with their approach; acquire a company, raise prices ten percent and cut labor costs by ten percent. Vale, fifteen percent to the bottom line. Each subsequent year a BTR plan begins with raising prices by inflation plus one percent and budgeting labor costs to increase by inflation less one percent. Very simple. Such is the norm for a BTR company. Suffice it to say that such an operation takes only an accountant to run and I submitted my resignation at the end of my contract, March 1992. Prior to leaving Sensym, I offered to BTR that I would purchase Sensym for a reasonable price rather than allow the fate of the gradual demise of the business operating under such a system. They decided to decline my offer. Sensym continues today in the BTR environment.


BTR and Siebe merged in 1997 and with this merger Sensym and Foxboro/ICT were consolidated under Chris Cartsonas. The ICT facility was sold and all operations consolidated with Sensym. Sensym's manufacturing is done primarily in Juarez, Mexico, with silicon processing still in Milpitas.


The Sensym name is being replace by Invensys Sensor Systems. This is a group name for all companies that were formerly the Sensor Group of BTR.


Art Zias

But what became of Art Zias you ask. During Christmas 1996 and New Year 1997, Art and his lovely wife, Ellie, toured Africa. There were reports their trip was partially funded by the Oakland school district for research into the true origins of Ebonics. Yet other reports have Art starting another sensor company or as lead saxophone for the Swahili military marching band. Based upon Art's background any one of the stories could, in fact, be true. Upon leaving National Semiconductor in 1982 Art went to be cofounder of Tricomp Sensors, ultimately a publicly funded company that went belly up thanks to the fine efforts of Ralph Voerst their principal investor and fund raiser par excellence. Art then founded Captorr along with professor Barry Block.


Barry is "the guru of variable capacitance, silicon to pyrex to silicon microstructures" having made a name for himself through the sale of the technology to Signetics in the seventies for automotive accelerometers. Each person associated with Barry has a different word for the "name" he has made for himself. I have found him to be incredibly interesting. However, it is a little bit disconcerting when all your meetings with him include his attorney and you have been told that he has made a significant amount of his money by way of lawsuits.


Captorr contracted with Dresser Industries to develop and "turn-key" a very low pressure (0.1 inch of water column full scale) variable capacitance differential pressure transducer. The technology developed for Dresser is now used in Dresser's low pressure devices and in some products manufactured though a Dresser Nagano joint venture in Japan. Other silicon pressure sensors manufactured in Japan by Fujikura, Nagano and others had there origins via technology transfers between Honeywell, Dresser, Foxboro ICT, and their Japanese partners. Captorr technology rights were sold to Dresser and Art and Barry left for other pursuits.


Art joined Teknekron Sensor Development Corp in Menlo Park, a company formed by a wealthy man, Harvey Wagner, residing on a ranch near Lake Tahoe. Apparently Harvey made a lot of money when he sold a credit report software company to TRW. Teknekron was formed for the purpose of developing companies in an incubator environment for the purpose of liquidity and provide a large return on investment to the principal investor, Harvey. The working principals where a handful of Phd's from industry and academia with interests in sensors of all types. The facility had state of the art sensor semiconductor and micromachining capability. In the end TSD, had its funding terminated when the forecast for the return on investment was determined to be too low. Four of the individuals, Martin Przybylski as President, Art as VP of engineering, Shawn Kahil in engineering and Norm Nystrom for facilities left to form a silicon gas flowmetering company called Fluid IC. This company had funding for the purpose of developing a replacement for the home natural gas meter and other monitoring system metering in the gas distribution business. Fluid IC was absorbed by Itron and ceased operation in 1995.


Art now consults through Ziasense, a "dba" of CapTorr. Art is an active consultant to several companies in the sensor industry. He provides a short tutorial on silicon sensor technology for newcomers to the technology or full courses for those skilled in the technology and business. Art also is an active director of MCA Technologies, a promising new company founded by Ali Rastegar, that provides ASIC signal conditioning circuits for sensors. To all that know Art he is truly a fine person and has been instrumental in the formation of the silicon micromachining industry. However, he's still has a horrible golf swing.


NeXt Sensors

In 1992 I retired for most of the year. Retirement is not what one might make it out to be, especially for one who has worked since he was twelve years old and enjoyed doing it. A friend of mine that retired in his forties after making enough money to do so from stock options would say "I don't miss the rat race but I do miss some of the rats!" I enjoy both, as long as you know what race you're in.


In early 1993 I informed Sensym I would be participating in the Sensor Show in San Jose and since I had a two year "not-to-compete" agreement they should determine what they might want to do. Sensym filed for a temporary restraining order to prevent me from participating in the show. The courts ruled against their request and I was allowed to attend with certain provisions. Sensym spent a considerable amount of legal time and dollars to attempt to keep me out of the sensor business. We had differing opinions regarding the not to compete provision that was finally settled by the courts. In the end, I learned a lot about the law and the legal system and Sensym spent a lot of money to prevent me from competing in the United States until June 1, 1994. I believe had Sensym spent all the money they spent on legal bills on product improvements they would be much better off today than they are.


Since I was having trouble getting started in the United States I exhibited at the Sensor Show in Nuremburg, Germany in May, 1993. I had a booth with no products, only some flowers and myself. Hans Keller stopped by and asked if I was now in the flower business. It was very fortunate I went to this show as I met Alexander Breitenbach. Alexander had just, within weeks of the show, left Sensortechnics Gmbh. Alexander had been the best salesman at Sensortechnics and the person responsible for a significant portion of their business. By the beginning of 1994, Alexander and I founded NeXt Sensors Gmbh and we were in the sensor business in Europe. At least, on paper we were in the business.


I incorporated NeXt Sensors in the United States and started production of some pressure sensors similar to Sensym's with improved performance in June, 1994. Two of the best people I have ever had the pleasure to work with joined me during the first month, Dale Dauenhauer, my brother and Marissa Magcase. Marissa had been our Quality Assurance manager at Sensym. Fred Adamic, who was Vice President of Engineering and Manufacturing for Sensym until 1993 join us in our facility, not as an employee rather he started his own company, Spectrum MicroDevices. Fred is still here, and Spectrum MicroDevices is still active. Fred is pursuing dielectrically isolated structures in silicon as well as some novel silicon gage structures. During the early days we received invaluable assistance from a couple companies and some needed financial support from some other people. Tim Shotter, founder of Gandolf who had designed the tire pressure gage for Sensym, provided product design support. Derek Bowers, founder of DB Design who had worked at Sensym ten years earlier provided package design and test fixture design support. I received financial support from Robertson & Stephens and from John Easton, president of Sensotec. The support from all was greatly appreciated.


By mid 1995 I recognized we would need more financial support than I could afford and I retained the services, again, of Harris-Roja to see what could be done. Since much of the investment was needed to establish a United States sales and marketing effort we decided to look for companies interested in a merger and use their existing infrastructure. In a short time period we had the interest of two companies, Data Instruments and Telcom Semiconductor. My personal interest was to work a deal with Telcom because I have known their Vice President of finance, Mike O'Malley, for close to twenty years and I was very favorably impressed by their CEO, Phil Drayer, who I had seen give a presentation at the Monterey AEA's Emerging Companies Financial Conference.


We merged NeXt Sensors with Data Instruments and created Data Instruments Advanced Silicon Group in December 1994. History has yet to write itself as to what will ultimately happen with DI-ASG.


In 1995 Data Instruments also acquired NeXt Sensors Gmbh and consolidated all Data Instruments European Marketing and Sales into the merged company Data Instruments -Next Sensors GmbH in northern Germany, close to Hannover.


In January, 1996 Sensymtronic, in Paris, France was acquired by Data Instruments and merged into Data Instruments France. The company president for each company continues with the respective operations.


In November, 1998 Data Instruments was sold to Honeywell. The ASG group (NeXt Sensors) was closed and moved to Freeport, Il. NeXt Sensors people assisted in the six month process of transition from Sunnyvale to Freeport. All key people remain in the Bay Area. All key people at Data Instruments in Acton, MA are no longer with the company.