In the past few years, the prosperity of chips has attracted attention to the semiconductor industry. Among them, transistors and MOSFETs are the basic components of chips, and we have also read many reports from many articles. In this article, we will explore in detail the origins and past and present lives of MOSFETs.
Early Exploration of FET
The first wave of semiconductor companies began in April 1952, when Bell Laboratories held the second transistor seminar for its transistor patent licensing, with representatives from approximately 40 companies participating. After the seminar, most of these companies began manufacturing bipolar contact transistors in just a few months or years, and many companies became successful commercial semiconductor suppliers. This includes Infineon (formerly Siemens), NXP (formerly Philips), and Texas Instruments, which are still manufacturing semiconductors to this day. In contrast, the development of metal oxide semiconductor (MOS) field-effect transistors (FETs) took decades, from ideas in the 1920s to initial working devices in the late 1950s, and then to commercial products in the 1960s. After years of scientific research, engineering design, analysis, and considerable publicity, this almost unnoticed device has been transformed into the backbone of today's semiconductor and electronic industries.
Julius Edgar Lilienfeld was the first person to apply for a patent for the idea of FET. Lilienfeld was born in the city of Lviv in 1882 and is now located in the western region of Ukraine. At that time, it was part of the Austro Hungarian Empire. On February 18, 1905, he obtained a doctoral degree from Friedrich Williams University (now Humboldt University) in Berlin and became an indefinite professor at the Institute of Physics there. His research focuses on electric field and electron emission induced by field. His early work focused on the magic device at that time: X-ray tube. He also conducted some early work on the behavior of electrons in high electric fields, which was ultimately thoroughly analyzed by physicists Ralph H. Fowler and Lothar Wolfgang Nordheim.
Lilienfeld first went to the United States in 1921 to defend his X-ray patent, opposing his seizure by a foreign custodian in 1919. He permanently moved to the United States in 1926 to escape the increasingly severe anti Semitism in Europe. In October 1926, he submitted the first of three patent applications based on his experiments in the semiconductor field. These patents essentially describe the conceptual basis of FET operations and were issued between 1928 and 1933. Lilienfeld holds a research and development position at Amrad, a radio parts manufacturer in Marton Hills, Massachusetts. There, he studied the electrochemistry and behavior of anodic aluminum oxide films, and his detailed analysis of these films formed the basis for manufacturing electrolytic capacitor for decades. Although Lilienfeld's three patents described the conceptual operation of field-effect transistors, the purity of the materials produced by the semiconductor processing technology at that time was far from the level required to manufacture such equipment.
Oskar Heil was the second person to independently conceive FET. He was born in Langston, Germany in 1908 and obtained a doctoral degree from George Augustus University in G ö ttingen. During his time at this university, he met Russian physicist Agnesa Arsenjewa, who was pursuing a doctoral degree. The two married in the Soviet Union in 1934 and moved to the British Cavendish Laboratory in Cambridge. They jointly wrote a groundbreaking paper on the generation of microwaves. They continued to engage in this work at the Institute of Physical Chemistry in Leningrad. Heil then returned to the UK without Arsenjewa. In 1934, while working at the University of Cambridge, Heil applied for a patent on controlling the current in semiconductors through capacitive coupling on electrodes, which is the fundamental element defining FETs. The patent was titled "Improvements in or related to electrical amplifiers and other control arrangements and devices" and was granted at the end of 1935. However, the available semiconductor purity at that time was very low and there was no necessary manufacturing process technology, which would once again hinder the practical implementation of this device, and there was no indication that Heil had attempted to manufacture field-effect transistors.
When Germany's invasion sparked World War II, Heil returned to Germany and began developing microwave generators for the C. Lorenz company located in Berlin Tempelhoff. There is a myth that has always existed, that Heil not only successfully manufactured field-effect transistors, but also used them to create a secret radio during World War II, but there is no evidence to suggest that Haier attempted to manufacture field-effect transistors. To make this myth a reality, Heil must figure out how to manufacture field-effect transistors in work, and then design circuits for field-effect transistor based radios in the era of tube radios. If you want to build a secret AM radio in the 1940s, it is much simpler and equally effective to use a variable inductance, a capacitor, a lump of galena and a steel cat whisker to make an audio detector. In addition, Heil works in a microwave laboratory in Germany. He can freely access many vacuum tubes. He is highly unlikely to want to manufacture a field-effect transistor so that he can manufacture a radio.
Although both Lilienfeld and Heil conceived FET, saying they invented FET is no more accurate than saying Leonardo DaVinci invented powered flight. According to the Smithsonian Institution National Air and Space Museum, DaVinci has created more than 35000 texts and 500 sketches about aircraft. However, we believe that the Wright brothers invented the first powered aircraft because they built and piloted the first such aircraft.
The Introduction of Transistors
William Shockley was born in London, England in 1910. His parents are Americans. He studied at Massachusetts Institute of Technology. In 1936, he received a doctor's degree, specializing in solid state physics. In the same year, Bell Laboratories hired him to conduct research on the possibility of using crystal semiconductors to manufacture solid-state amplifiers. In 1939, William Shockley wrote: "Today I think that it is possible to use semiconductor instead of vacuum amplifier in principle." William Shockley seemed unaware of the patent granted to Lilienfeld and Heil earlier.
Shockley and Walter Brattain developed a FET before the start of World War II, but it was unsuccessful. The war temporarily halted this work, but after the war ended, Shockley added John Bardeen to the team. Through a series of physical experiments, Brattain and Bardeen finally created a working point contact transistor on December 16, 1947, with a gain of approximately 100 in the audio frequency band. However, coincidentally, this first transistor is not a field-effect transistor. It is a bipolar transistor and does not operate based on an electric field.
Bell Laboratories announced the invention of the transistor on June 30, 1948. The 6-month delay gave Bell Labs patent lawyers time to complete the patent application. Before Brattain and Bardeen made a breakthrough, Shockley had already moved away from his daily work and more focused on serving as a consultant and manager. But now that this feat has been completed, he is ready to become a member of the team again and insists on standing in front and in the middle when taking any public relations photos. He also decided to devote himself to his patent application, insisting that the transistor he had created was a FET. The patent lawyers of Bell Labs refused to work for William Shockley's patent application because it was too similar to Lilienfeld's patent in the late 1920s and early 1930s, and they deleted his name from the original transistor patent of Bell Labs for the same reason.
After the demonstration of the transistor in June 1948, William Shockley madly carried out a month's theoretical analysis of its operating mechanism. He confirmed that the transistor effect of the point contact device comes from the P-N semiconductor junction. Based on this insight, William Shockley quickly conceived the sandwich transistor, which is the first of a new variety of devices called node transistors. If you see a simplified diagram of a bipolar transistor, it usually depicts a sandwich transistor with the base as the interlayer filler, located between the emitter and collector of the transistor.
When Bell Labs announced the launch of the junction transistor in 1951, it quickly became the dominant transistor in the industry because it outperformed the original point contact devices in all aspects. However, it is still a bipolar transistor, not a MOSFET. In 1950, William Shockley devoted his analysis to the first important book on semiconductor transistors, titled Electronics and Holes in Semiconductors: With Applications to Transistor Electronics. This book has been the Bible of the semiconductor industry for many years. Shockley, Bardeen, and Brattain shared the 1956 Nobel Prize in Physics for their semiconductor research and discovery of transistor effects.
Frustrated by the lack of promotion at Bell Laboratories, William Shockley moved to his hometown of Palo Alto, California, and founded his own company, William Shockley Transistor Laboratory, in 1955. He did not engage in MOSFET development work there. He has turned to bipolar and has developed a strong interest in a project at Bell Labs - a 4-layer diode. William Shockley Transistor Lab has obtained the authorization of Bell Labs transistor patents. William Shockley himself continues to keep close contact with Bell Labs researchers, bringing many semiconductor process innovations to the San Francisco Bay Area, which will quickly promote the establishment of Silicon Valley.
Mohamed Atalla and Dawon Kahng from Bell Labs became the first to construct working MOSFETs. Atalla was born in Port Said, Egypt. He studied at Cairo University in Egypt and obtained master's and doctoral degrees from Purdue University in the United States. Atalla joined Bell Laboratories in 1949. Dawon Kahng was born in Seoul, South Korea in 1931, when South Korea was not yet known as South Korea. He studied physics at Seoul National University in South Korea, immigrated to the United States in 1955, and obtained a doctoral degree from Ohio State University in 1959. In the same year, he joined Bell Labs.
The development of the first MOSFET by Atalla and Kahng was based on early research conducted by Carl Frosch and Lincoln (Link) Derick at Bell Laboratories, who unexpectedly discovered a method of growing a layer of silica on silicon in 1955. By 1957, Frosch and Derick had perfected this idea and added the concept of using silica layers as silicon doped diffusion masks. They published an article titled "Surface Protection and Selective Masking During Diffusion in Silicon" in the Journal of the Electrochemical Society in September 1957, discussing this issue.
Importantly, Bell Labs' approach is to remove the silica layer after diffusion, as it is considered 'dirty', just like 'carrying pollutants'. Two months after Frosch and Derick's article was published, Jean Hoerni of Fairchild Semiconductor realized the importance of the silica layer for several reasons that it should be left in place. The pure silica layer has become an integral part of Hoerni's planar manufacturing process and will become a key factor in integrated circuit manufacturing.
Atalla further refined this discovery into a more formal silicon dioxide passivation technology, which combines with newly developed lithography and etching techniques to allow for more precise incorporation of silicon at specific locations. Using this technology, Atalla and Kahng successfully manufactured a working MOSFET in early 1960, thirty years after Lilienfeld first conceived the device. Although the device can work to some extent, there are several issues with this first MOSFET. It is worth noting that it is 100 times slower than contemporary bipolar transistors, mainly because its channel length is relatively large, at 20 micrometers.
Due to the very slow speed of this initial MOSFET, Bell Labs was not interested in it, and Atalla and Kahng received little honor in their development. Despite a lack of honor and interest, Atalla and Kahng continued to research semiconductors and developed p-channel and n-channel MOSFETs, the first working Schottky diode, and the first nanoscale gate bipolar transistor, which sandwiched a thin metal gate between the semiconductor base and emitter - only a few nanometers thick. The thin base structure enables this transistor to operate at much higher frequencies than bipolar transistors at the time.
Due to being tired of her job and not receiving recognition, Atalla left Bell Labs and joined HP in 1962. He helped the company establish its own semiconductor laboratory, HP Associates, and became the director of the semiconductor research department. Then, in 1966, he helped create HP Labs and became the first person to guide its solid-state department. In 1969, Atalla left HP to become the Vice President and General Manager of the Microwave and Optoelectronics Division at Fairchild Semiconductor. Prior to this, he led research on gallium arsenide materials at HP.
Kahng stayed at Bell Labs for many more years. He applied for a patent for MOSFET in 1960 and obtained it in 1963. Together with colleague Simon Min Sze, Kahng developed floating gate MOSFETs in 1967. This invention is the core storage element used in EPROM and EEPROM. Kahng retired from Bell Labs in 1988 and became the founding chairman of NEC Research Institute, now known as NEC American Laboratory, which is the American center of NEC's global enterprise research laboratory network.
Kahng stayed at Bell Labs for many more years. He applied for a patent for MOSFET in 1960 and obtained it in 1963. Together with colleague Simon Min Sze, Kahng developed floating gate MOSFETs in 1967. This invention is the core storage element used in EPROM and EEPROM. Kahng retired from Bell Labs in 1988 and became the founding chairman of NEC Research Institute, now known as NEC American Laboratory, which is the American center of NEC's global enterprise research laboratory network.
Atalla and Kahng won the Stuart Ballantine Award at the Franklin Institute Award in 1975 for their invention of MOSFETs. After decades of theoretical research, they proved that manufacturing a MOSFET is possible. However, the initial equipment was problematic. They are slow, their characteristics change with temperature and time, and they are unreliable. No application requires a slow and unreliable transistor. The exploration of better MOSFETs and suitable applications has been accepted by MOSFET evangelists from several companies. Along the way, MOSFETs have become faster and more reliable. When the dust settled a few years later, many people contributed to the ultimate success of MOSFETs, but this was not an easy journey. There are many technical issues to overcome, corporate politics to avoid, and business barriers to overcome.
The Rise and Fall of Xiantong Semiconductor
No company is more qualified and qualified to take advantage of the development of the first MOSFET than Xiantong Semiconductor. The company was founded in 1957 and engaged in research on silicon transistors. Jean Hoerni developed planar processes. Robert Noyce proposed the first practical integrated circuit (IC) based on the Hoerni planar process a few months before Atalla and Kahng got their first MOSFET job at Bell Labs. Just like the two keys needed to open a safe in a bank vault, planar semiconductor technology and planar integrated circuits are the two keys needed to unlock the full potential of MOSFETs.
Xiantong Semiconductor possesses these keys, and although its researchers have made significant contributions to the development and improvement of MOS, the company has not been able to create a successful MOS integrated circuit product line. As a result, as Moore's Law pushed the density of integrated circuit devices beyond the scope of bipolar transistor technology and entered the tempting MOSFET field, the company witnessed the disappearance of its early leading position in the field of integrated circuits - bipolar integrated circuits.
William William Shockley left Bell Labs in 1953 because he felt neglected in promotion and recognition. He moved back to California and worked at the California Institute of Technology. He reached an agreement with Arnold Beckman, a professor of the California Institute of Technology and a high-tech entrepreneur, and established the William Shockley Transistor Laboratory in 1955. At first, William Shockley thought he could raid Bell Labs personnel, but none of his former employers were willing to cooperate with him. He was forced to search elsewhere and managed to form a super team of young, recently graduated scientists and engineers, leading them to the super weather in California. He also promised that they would develop today's Holy Grail, which is silicon transistors.
The next year, William Shockley shared the Nobel Prize in Physics with John Bardeen and Walter Brattain for inventing the point contact transistor. Around that time, William Shockley became very interested in the four layer diode. This semiconductor switch had a great interest in Bell System. However, this is not the equipment he promised his researchers, and they are not happy. William Shockley's autocratic management style and conceit split his team, leading to a showdown on May 29, 1957. The research group's request is to solve the "William Shockley problem". It was not resolved, and the eight members of William Shockley's research team - later known as the "traitor eight" - left in September 1957. This core group reached an agreement with Sherman Fairchild Company to establish Xiantong Semiconductor on October 1, 1957. Xiantong Semiconductor Company will quickly become the world's most important semiconductor company and is also the most likely company to elevate MOS transistors to their full potential.
The first important step in realizing the fate of Xiantong Company was the invention of the planar semiconductor process. On December 1, 1957, just two months after the establishment of Xiantong Company, Hoerni suddenly gained inspiration. He knew that Bell Laboratories was working on passivation, photolithography and etching of silicon dioxide, because William Shockley had discussed this problem with his research team earlier that year before the "Rebellious Eight" left. Hoerni only used two pages of paper in his laboratory notebook to describe the flat process. His innovation is to leave thermally grown silica on semiconductor wafers after diffusion to protect the underlying circuits. Bell Labs believed that this oxide was too dirty to stay in place, but Hourney realized that a sufficiently clean insulation layer could prevent pollution from dust, dirt, and water. With almost no modifications, Hoerni applied for a patent for the flat process on January 14, 1959.
The second important step towards achieving semiconductor breakthroughs occurred on January 23, 1959, which was a necessary condition for MOSFETs to achieve their destiny. On that day, Robert Noyes, the founder of Xiantong Semiconductor Company, wrote down his ideas about single-chip integrated circuits in his laboratory notebook. He has been thinking about how to use Hoerni's planar process to manufacture more discrete transistors. He realized that the silicon dioxide layer is a perfect insulator that allows metal interconnects to be deposited on it to complete the connection between multiple devices on an integrated circuit. With this shining insight, Noyes has forever transformed the electronics industry and transformed welding and wiring into high-tech printing processes.
These two ideas, namely Hoerni's planar process and Noyce's integrated circuit concept, ignited the fuse of Xiantong. Firstly, Xiantong Company utilizes planar technology to manufacture transistors that are better and more stable than any competitors. The transistor of Xiantong Semiconductor quickly became the gold standard. Within two years, Xiantong Semiconductor announced the world's first integrated circuit product series, known as Micrologic. This is a bipolar logic integrated circuit series. In the six months after the launch of the Micrologic series, Xiantong Semiconductor swept the entire field. Xiantong Semiconductor's competitors have nothing to offer to their customers like Xiantong Semiconductor's ICs. Even Texas Instruments, which officially became the co inventor of the integrated circuit, had to license Xiantong's integrated circuit patent in order to compete.
Shortly after Mohamed Atalla and Dawon Kahng put their first device into operation in 1960, Gordon Moore learned that Bell Labs had successfully developed the first MOS transistor. In 1959, after Robert Noyes became the general manager of the company, Moore took over as the director of the R&D department of Xiantong Semiconductor. Edward Baldwin, who was hired to hold this position at the time, and five other Xiantong Semiconductor employees suddenly resigned and founded Rheem Semiconductor.
A week after Baldwin left, Xiantong Company tested the first bipolar transistor manufactured using Hoern's planar process. The transistor operates well. There is a saying that Hoern spits water into the transistor during testing to prove that the planar process prevents contamination of the transistor. Perhaps the actual testing was not as exaggerated as using Hoern's saliva samples, but the flat process did achieve the expected results. Gee, Baldwin had to leave last week, that's too bad, "recalls Jay Last, co founder of Xiantong Company. Xiantong Company has been producing mesa transistors and within a few months, will shift production to far superior and more stable planar transistor designs.
With the new planar bipolar transistors and Micrologic integrated circuits, Xiantong Company's work becomes very fulfilling. It aims to ensure the reliability and stability of planar processes, learn and implement precision lithography techniques required for manufacturing integrated circuits, and develop new bipolar transistors and Micrologic chips. There are no customer requests or even inquiries from Xiantong regarding MOS transistors, so no one is developing them. Gordon Moore's research and development department focuses on long-term projects, which do not include MOS transistors.
In 1962, Fairchild Semiconductor Company hired Frank Wanlass, a newly appointed Ph.D. in physics from the University of Utah, changing his indifference to MOS. When he joined the company, Wanlass was already fascinated by MOS transistors, and he knew that Xiantong's planar process was the method of manufacturing MOS transistors.
Wanlass was hired to the R&D department of Xiantong Company, and his task gave him enough room to study MOSFETs, even though Xiantong Company did not produce MOSs at the time, as MOS metal oxide semiconductor structure was a component of planar technology, whether used for manufacturing bipolar or MOS transistors. His freedom largely comes from his ability to do almost everything on his own. As a physicist, Wanlass understands the physics of MOS structures and is therefore able to design MOSFETs himself. He understands electronics, so he not only designed transistors, but also circuits that enter MOS integrated circuits. One of his earliest designs was an integrated MOS trigger with a traffic rate of over 80%. In February 1963, Wanclass and his manager C.T. Sah published a paper on ISSCC, revealing that Wanclass had conceived a circuit that combines p-channel and n-channel MOSFETs on the same integrated circuit. He invented CMOS, which is just a byproduct of his work.
In this process, Wanlass addressed the inherent stability issues of MOSFETs and Xiantong's general disregard for MOSFETs. The company has done so well in manufacturing bipolar semiconductor products that it has invested a lot of effort in slow MOSFETs. Although Gordon Moore's research and development department has invested a lot of effort in analyzing and simulating MOS physics as a way to improve planar processes, the goal of these improvements is the manufacturing of bipolar transistors. By December 1963, Wanlass felt frustrated and switched jobs. He joined General Microelectronics (GME), a company founded by members of the Micrologic group of Xiantong Semiconductor in the summer of 1963, with the specific purpose of developing MOS integrated circuits.
With the loss of several key members of Micrologic Group and Wanclass Company, Xiantong's popularity has gone forever, and the company has never developed a series of MOS integrated circuit products. In the end, Moore himself realized that Fairchild Company had not fully realized the potential of MOSFETs. When he left Fairchild Company with Robert Noyes in 1968 to establish Intel, he would create a semiconductor company specializing in the production of MOS integrated circuits - specifically memory integrated circuits - but this event had been going on for nearly five years.
The Birth of MOSFETs
It is not surprising that in the early 1960s, semiconductor companies were unwilling to invest a lot of effort in the development of MOSFETs. Early MOSFETs were 100 times slower than bipolar junction transistor, and they were considered unstable for a reason: their electrical characteristics drifted severely and unpredictably with the change of time and temperature. Transforming MOSFETs into reliable electronic components requires extensive research and development work.
However, when Fairchild Semiconductor hired Frank Wanlass, MOSFET found its supporters. Wanclass is committed to the research of MOSFETs, not any company. He went anywhere and did anything to promote the development of MOSFETs. He became Johnny Appleseed of MOS (Metal Oxide Semiconductor) technology, freely sowing the seeds of MOSFETs anytime, anywhere.
Xiantong Company hired Wanlass in August 1962, when he obtained a PhD in physics from the University of Utah. When he was studying for his doctorate in solid state physics, he read RCA's work in thin film cadmium sulfide (CdS) field-effect transistors, and became interested in MOS technology. The simplicity of FET device structure first piqued his interest and then fascinated him. He realized that the simple structure of field-effect transistors meant that many field-effect transistors could be installed on a semiconductor chip, and he envisioned using these devices to build complex integrated circuits (ICs). But the thin film CdS FET of RCA is too unstable. Even if left on a shelf for a few hours, their electrical characteristics will undergo significant drift. Wanlass believes that using silicon instead of CdS to manufacture FETs will solve the problem of parameter drift. The facts proved that he was wrong. Semiconductor field-effect transistors suffered from drift for several years until the MOS manufacturing process was sufficiently cleaned to eliminate the pollutants that caused the drift of field-effect transistor parameters.
When Wanlass joined Gordon Moore's research and development team at Fairchild, the company had a policy of allowing newly hired doctoral students to work on any project they were willing to undertake. Wanlass has decided to focus on MOSFETs, although Moore's department is not particularly interested in manufacturing such devices. However, Moore's department is very interested in MOS processing, as it is the fundamental structure and properties of Jean Hoerni's planar manufacturing process, which Xiantong Company uses to manufacture bipolar transistors and integrated circuits. Any further understanding of planar processes and any improvements in process technology will further enhance Xiantong Semiconductor's ability to manufacture bipolar transistors and integrated circuits.
Wanlass is not interested in studying or analyzing the characteristics of MOS processes. He wants to manufacture discrete MOSFETs, use MOSFETs to manufacture ICs, and use these devices to design system level circuits to cultivate demand for these components. In the following year, he did exactly that. In less than six months, Wanlass designed and manufactured single p-channel and n-channel MOSFETs in silicon using a planar process. All p-channel devices exhibit severe parameter drift, while n-channel devices are not functioning at all. He tested the parameter drift of the p-channel device by placing it in a curve tracker and heating it with a lighter. Then, he designed and manufactured a trigger IC using MOSFETs, achieving an incredible wafer yield of over 80%. He developed application circuits for MOSFETs, including an ammeter that utilizes the extremely high input impedance of MOSFETs.
During this process, Wanlas and his manager C.T. Sah applied for a patent for the idea of a CMOS circuit that combines p-channel and n-channel MOSFETs on a silicon chip. CMOS is the fundamental transistor technology for almost all integrated circuits manufactured today. (Note: Sah is often listed as the only inventor of CMOS, but his name appears on the patent because he is the manager of Wanlass, and it is customary to list the manager and inventor together in patent applications.)
In early 1963, Gordon Moore began hiring more people to conduct a more thorough analysis of MOS process technology. However, he is not interested in studying MOSFETs. He just wants to better understand the metal oxide semiconductor planar process, so that Xiantong Company can manufacture better bipolar transistors and integrated circuits. The analysis team became Bruce Deal, Andrew Grove, and Ed Snow. They were not arranged in a formal team, but they quickly discovered complementary tasks from each other through accidental interaction in the office Deal is engaged in research on oxidation and surface state. Snow analyzed the transient instability of MOS. Grove wrote a program to simulate analysis.
By the end of 1963, Wanlas was convinced that Xiantong Company only wanted to research and analyze MOS devices, rather than manufacturing them commercially. He preferred manufacturing devices rather than researching them. Wanlass left Xiantong Semiconductor in December 1963, just one year and four months after joining the company. He works at General Microelectronics (GME), which was founded by a small group of former Xiantong employees who decided to establish a semiconductor company. GME was one of the earliest spinoff companies of Xiantong Semiconductor, collectively known as "Xiantong". The goals and directions of GME will obviously bring Wanlass to the place he wants to go, and Wanlass will immediately be responsible for creating and manufacturing MOS transistors and ICs.
Wanlass brought his exquisite MOS design skills to GME. He successfully manufactured MOSFETs and small MOS integrated circuits at Xiantong Company, so he brought these capabilities, but he also brought another important thing. When working at Xiantong Company, Wanlas found that if he used electron beam vaporization instead of thermal evaporation to evaporate aluminum interconnects on semiconductor chips, he could greatly reduce the time and temperature drift of MOS characteristics. Xiantong Company has been building electron beam evaporators in its basement. It was one of the earliest semiconductor companies to have this type of evaporator.
In an interview, Wanlass said: One day, I was driving on the 101 highway and on a Sunday, it hit me. This must be sodium, and I sent some aluminum wires for spectral analysis. I learned from my university work that some of my paper work, sodium... I know the fact that sodium, with just a little help from temperature and voltage, will directly diffuse through quartz. It has a very high diffusion quotient. I know this. That's in university Experiments conducted. "
Due to suspicions that the thermal vaporization process would to some extent deposit contaminated aluminum on semiconductor chips, which caused device drift, Wanlass attempted to evaporate platinum onto the chips instead of aluminum. Platinum was not chemically etched, so he had to manually mark the gate on the platinum layer with a pointed tungsten probe. The resulting MOSFETs have almost no drift. Then he tried using gold and other metals, but platinum was even better. Then, for completeness, Wanlass used an electron beam evaporator to place the aluminum on the wafer. They did not drift as much, and electron beam evaporation of aluminum quickly became a part of the MOS process formula. All of this happened when Wanlass was still at Xiantong Company, and he brought these important knowledge to GME.
Ultimately, the industry will understand that sodium ion pollution can lead to drift and kill p-channel MOSFETs over time, while making it impossible to establish working n-channel MOSFETs. When aluminum is pulled through the wire mold to manufacture aluminum wire as a vapor deposition material, it is contaminated with sodium. The wire mold is lubricated with sodium. Electron beam vaporization uses a shutter mechanism to shield the silicon wafer from the crucible for melting aluminum until the aluminum reaches its evaporation temperature. The boiling point of sodium is much lower than that of aluminum, so before the shutter in the evaporation chamber opens and exposes the wafer to aluminum vapor, sodium has already boiled and dissipated.
Wanlas used an electron beam evaporator to metallize wafers at GME, and by May 1964, he had produced a working, discrete MOS transistor. The company commercialized this device several months before Xiantong was able to achieve this. Then, Wanlass manufactured a single chip MOS integrated circuit with a 20 bit shift register, not because of the customer's requirements, but simply because he was able to do so. The 20 bit shift register is a very good demonstration carrier for MOS ICs. At that time, shift registers were the industry's preferred form of small digital storage devices due to their small number of pins and allowing devices to be installed in TO-5 metal can transistor packages with up to 12 pins.
Although GME had a booth at the WESCON (Western Electronics Exhibition and Conference) held in Los Angeles in 1964, the company also rented a hotel room solely to showcase Wanlass's shift register integrated circuits. GME's demonstration of MOS shift register integrated circuits left a deep impression on potential customers, firmly establishing GME's leadership position in MOS integrated circuits, and positioning Wanlass as an industry authority in MOS integrated circuit development.
GME's MOS shift register integrated circuit demonstration, the company's reputation as a MOSFET supplier continues to improve, and the sales skills and relationships of Art Lowell, one of the founders of GME and retired colonel of the United States Marine Corps, have attracted customers from the US government. The company's first MOS design contract was signed with the National Aeronautics and Space Administration (NASA) to design an integrated circuit with six or seven MOSFETs for the interplanetary monitoring platform spacecraft, managed by the NASA Goddard Space Flight Center in Greenbelt, Maryland. Spacecraft have strict power limitations, so low-power MOS integrated circuits seem to be tailored for this project. The highly confidential National Security Agency (NSA) has also become an early customer of GME. Wanlass recalled that the National Security Agency had an ambitious plan to place wireless communication with decryption circuits in soldiers' helmets.
The device density has set GME on the path to the early fate of MOS integrated circuits: calculators. GME has signed a protocol with Victor Calculator to establish a MOS calculator chipset consisting of at least 20 ICs, each containing hundreds of circuit components, including MOSFETs. This should have been a dream project for Wanlass, but he can see that GME will not be able to meet this challenge. Wanlass left GME in December 1964, when the calculator project had just begun. As he expected, GME's calculator project was plagued by delays. The company began to experience financial problems and was acquired by Philco Ford in 1966. It became the microelectronics department of Philco Ford, and the brand of General Microelectronics no longer exists. Philco Ford ultimately abandoned the Victor calculator project in 1968, and a few years later Ford decided to sell it, and the company itself no longer existed. GME went bankrupt because they didn't have enough money and they pushed too quickly and too urgently, "Wanlass said in an interview.
When he left GME, Wanlas and his four colleagues first attempted to establish their own semiconductor company, but the transaction failed. On the contrary, the team joined General Instrument, an East Coast electronics group that hopes to incorporate semiconductor manufacturing, especially integrated circuit manufacturing, into its investment portfolio. GI has hired managers from other semiconductor manufacturers, including Philco and IBM. Joining Wanlass and his team has determined the direction of the new semiconductor department: MOS.
The first thing Wanlass did at GI was to design and manufacture a 21 bit shift register IC, which is one bit larger than GME's device, so that GI can claim to have the largest device. Soon, GI introduced 50 bit and 90 bit MOS shift register ICs. Then, what Wanlass did during his tenure at GME brought him a return on investment. In 1964, when Wanlass was demonstrating GME's 20 bit shift register in a hotel suite at WESCON, he met an engineer named Bob Booher who was working at Rockwell Automotive, an avionics contractor known for developing inertial guidance systems for American submarines and ICBMs. During that meeting, Wanlass seemed to have infected Booher with his passion for MOS integrated circuits.
A few years later, Booher found Wanlass at GI and asked if GI could manufacture a chip he designed. This is a Digital Differential Analyzer (DDA), which was a very ambitious device in that era. Booher's DDA is the digital implementation of Vannevar Bush's differential analyzer. Before the advent of digital electronic computers, this mechanical analog computer was widely used to solve differential equations numerically. Ultimately, Rockwell Controls will establish its own semiconductor manufacturing team, but that is in the future, and Rockwell was unable to manufacture such large chips at that time. The chip design requires thousands of transistors, which is the most complicated integrated circuit design that Wanlass has ever seen. In addition, Booher has developed a novel 4-phase clock scheme that can generate fast dynamic logic gates while saving silicon space. Wanclass agreed to manufacture the chip for Booher, and the device has been successful. In August 1966, GI displayed this device, and Buch was ecstatic.
By 1967, Wanlass's notorious lack of patience had once again become apparent. He made a deal he didn't like, but this time, it was a location issue that troubled him. GI's semiconductor facility is located in Hixville, Long Island, New York. Wanlass grew up as a Westerner who didn't like the weather on the East Coast or the labor force of the union. He suggested transferring GI's entire semiconductor business to the state of Utah where he grew up. To make him happy, GI allowed Wanlas to establish a research and development laboratory in Salt Lake City, Utah, where he obtained his doctoral degree. Considering the impact of sodium on MOS integrated circuits, a small town called Salt Lake City may not be an ideal location for MOS semiconductor laboratories, but this transaction allowed Wanlas to continue working for GI, at least for a few more years. The laboratory was completed in August 1967. During this period, GI became a leader in MOS integrated circuit design and manufacturing. In 1970, Wanlass left GI, and the company's position in the integrated circuit industry rapidly deteriorated thereafter.
As an energetic MOS evangelist, Wanlass directly or indirectly helps some companies enter the MOS integrated circuit business. The researchers of Xiantong Semiconductor continue to benefit from his work there. In March 1965, Wanlass met with the personnel of IBM Research Institute and shared his knowledge in MOS integrated circuit design with them. The IBM Research Institute quickly became a focus of MOS research. In 1966, Fairchild Company hired Lee Boysel from IBM. Although he works for IBM, he is basically an apprentice at GI, so when he joined Xiantong Semiconductor, he was familiar with various aspects of MOS IC technology, including Booher's 4-phase clock scheme. In 1969, Boysel established his own computer and MOS semiconductor company - Quad Phase Systems. Xiantong Semiconductor also hired Bob Cole from GME, who worked as the Chief Engineer with Wanlass in GME's MOS manufacturing business. According to reports, Texas Instruments' first MOS integrated circuit was a reverse engineering copy of the GI chip designed by Wanlass.
When Gordon Moore co founded Intel in 1968 to manufacture MOS memory integrated circuits, he attempted to hire Wanclass, but Wanclass signed a 7-year contract with GI and rejected the proposal. However, Intel's chief MOS engineer participated in GI's seminar, where Wanlass provided a detailed introduction to GI's MOS work. Wanclass eagerly shares information at all times, as his main goal is to make the industry's use of MOS integrated circuits more prosperous. This is not to say that Wanlass cannot keep secrets. Before obtaining his doctoral degree, he spent several years in the US Army Special Forces, dealing with the secrets of atomic weapons, and he was tired of keeping secrets.
The history of semiconductors often describes Wanlass as "impatient," which is reasonable. As long as he believes it is beneficial for the development of MOSFET, he will leave his employer to search for a broader world. The semiconductor industry is indeed very lucky, he is so impatient. His persistence urges him to go to any place where he has the best opportunity to help MOSFET realize the destiny he envisioned when he was a doctoral student at the University of Utah. No matter it needs to change employers, make detailed technical report to researchers of other semiconductor manufacturers, provide a large number of free suggestions upon request, and even take profits from competitive semiconductor suppliers.
The historical records of Wanlass disappeared quickly after he left GI in 1970. He seems to have moved to California and Silicon Valley. After leaving GI, Wanlass worked for several start-up semiconductor companies, founded or participated in them, including:
Varadyne is a widely based electronic component manufacturer based in Santa Monica, California. It acquired Integrated Systems Technology, a MOS design company that separated from GME after being acquired by Philco Ford in 1966.
LSI Systems, a CMOS watch chip manufacturer based in Sunnyvale, California, was acquired by John Marshall in 1976 and renamed Integrated Technologies, retaining Wanlass as the design consultant.
Four Phase Systems, a computer and memory chip manufacturer based in Cupertino, California.
Ultra Logic, a CMOS process consulting company from Wanclass, developed and patented the early BiCMOS process, called UltraCMOS, which combines CMOS logic with bipolar output transistors.
Zytrex, a company based in Sunnyvale, California, acquired UltraLogic from Wanlass in 1981 and appointed him as its Chief Technology Officer.
Standard Microsystems, based in Harpark, New York, was acquired by Microchip in 2012.
When Wanlass served as the Chief Technology Officer, Robert Plachno was the Vice President of Engineering at Zytrex Company. Plachno recalled that Wanlass could sit down and design a new CMOS process using a pencil and a piece of paper, writing down the tool flow and the time and temperature required for each process step in an orderly manner on the paper. He also recalled that Wanlass would manually design a new integrated circuit on an E-sized Mylar paper, using a table tennis table in his garage as a work table.
In 1991, Wanlass became the third recipient of the IEEE Solid State Circuit Award, now known as the IEEE Donald O. Pederson Award for Solid State Circuits. On the occasion of the 50th anniversary of the invention of MOSFETs and integrated circuits in 2009, Frank Wanlass was inducted into the National Hall of Fame for inventing CMOS circuits. In 1994, he retired but continued to tinker with electronics and computers.
In the end, Wanlass's vision of MOS integrated circuits became a reality. He passed away in 2010, giving him ample opportunity to see MOSFETs and CMOS become the fundamental circuit components of almost all integrated circuits today. His personalized California license plate reads "I LUV CMOS", which is a suitable message for the industry's first MOS evangelist。