One of IBM’s most important MOS Technology, 1963-1974: A Dozen Crucial Years contributions to MOS research came from the Components Division, which was responsible for developing by Ross Knox Bassett and manufacturing bipolar transistors for its large computer systems and had very little interest in MOS transistors line can be drawn from the as such. As part of its work on Frosch’s and Derick’s work on bipolar transistors, Donald Kerr and silicon dioxide to the MOS (metal- a group of engineers had discovered A that depositing small amounts of oxide-semiconductor) transistor’s domi- nance of semiconductor technology, phosphorous on the silicon-dioxide but it is neither short nor straight. That surface and forming a layer of line has several discernable segments, phosphosilicate glass (PSG) could first from Frosch and Derick’s work, limit the amount of leakage in bipolar until 1963. In this interval, by and transistors and play an important role large, no one thought seriously about a in enhancing the stability of MOS metal-oxide-semiconductor as a viable transistors. Jerome Eldridge and Pieter technology in its own right. The second Balk from IBM Research implemented segment runs from 1963, when the this work by using thin layers of combination of integrated circuits and PSG to make stable MOS devices. the planar manufacturing process had Other important work on the physics FIG. 2. Drawing of Atalla and Kahng’s “silicon-silicon dioxide surface device,” now known as and chemistry of MOS devices done led people to see MOS transistors as a the MOS transistor, from a 1961 Bell Labs technical memorandum by Kahng. (Courtesy AT&T potentially promising semiconductor Archives and History Center) by IBM included an examination of technology, until the mid-1970s, at the important role of annealing in Between 1964 and 1967 Deal, Grove which point the MOS transistor had aluminum structures. He then tried enhancing the surface conduction of and Snow, along with their manager C. been established as a commercially applying aluminum with an electron- MOS devices, and a demonstration of T. Sah, published over two dozen papers successful and sustainable technology. beam evaporator and discovered the advantages of using silicon with a related to the silicon-silicon dioxide This article will detail that second that the key to stability was not the crystal orientation (100) for making interface, which to all appearances 7 segment, concentrating on work done by particular metal used, but the method MOS devices. put the MOS structure on a firm Fairchild Semiconductor Corporation of evaporating it. He then purposely In spite of all the work IBM scientific footing. The achievements and IBM, and will show that three contaminated devices with sodium, Research did on MOS technology, it of the trio were most clearly seen in types of work were crucial during this lithium, magnesium, or calcium and faced an inherent difficulty in getting a semiconductor physics course that period: first, research on the chemistry ascertained that sodium led to the the rest of the company interested in they put together with other Fairchild and physics of MOS structures; second, highest drifts. (Researchers later found the technology. This lack of interest researchers. Its centerpiece was the trio’s product design and development to that the tungsten filament wire used occurred because MOS transistors were research. Grove published the course create integrated circuits that had some in the evaporation process had been inherently much slower than bipolar FIG. 1. First two pages of Frank Wanlass’s U.S. patent on complementary MOS transistor circuitry. notes as a book, Physics and Technology advantages over bipolar technologies; extruded through a die lubricated transistors in the 1960s, given the gate of Semiconductor Devices, which became and third, organizational change with sodium, and was therefore lengths then achievable. IBM, which the authoritative text in the field for a to create environments where MOS simultaneously evaporating sodium made most of its money from large his CMOS circuitry and the low MOS transistors useless as a product. If generation.5 technology could thrive. and aluminum.) Snow’s work led to computer systems, wanted transistors power consumption it allows has been these problems could be solved, MOS an effort to search for and minimize But in spite of the work of this group, with speeds as fast as practically one of the technical foundations of transistors would be technically viable. sodium in any materials used in the Fairchild was able neither to consistently possible. Skepticism about the value Early Research at Fairchild MOS’s dominance over the last three The first member of the group was MOS production process.3 make stable MOS devices throughout of MOS technology reached the point decades. Wanlass, who often worked Bruce Deal, who came to Fairchild in Another focus of the group was the organization nor to develop a that in October 1965, IBM’s Corporate In its earliest years, Fairchild had put at the very edge of what was possible, March 1963 with a PhD in chemistry surface states. In the late 1940s, John successful MOS product line. Problems of Technical Committee directed a lot of time and effort into studying seldom published and bounced around from Iowa State University and many Bardeen had developed a theory technology transfer hampered Fairchild’s IBM Research to halt work on this the surfaces of bipolar transistors, among marginally successful MOS years researching oxidation processes. of surface states to account for the ability to make stable devices in both its technology. But IBM Research refused but the first sustained work on the companies, and is one of the vastly Andrew Grove joined later that spring failure of experiments suggested by development groups and its Mountain to do so, and the Corporate Technical MOS transistor as a potential product under-recognized figures in the history after receiving his PhD in chemical William Shockley and executed by View manufacturing facility. This would 1 Committee was unable to enforce its came from Frank Wanlass, who of MOS technology. engineering from UC Berkeley, where Walter Brattain and others in hopes have been a serious problem if Fairchild decree within the corporation.8 joined Fairchild in August 1962 after After Wanlass’s MOS transistor work he had worked on fluid mechanics. of building a solid-state amplifying had developed any MOS products that The doubts within IBM about MOS earning a PhD in physics from the in early 1963, Gordon Moore, then Ed Snow came later that year from the device. Bardeen proposed that the people really wanted to buy, but as of technology, verging on downright University of Utah. In a period of director of research and development University of Utah, where he had earned cause of the failure was surface states, 1968 the company had developed MOS hostility in some quarters, led IBM remarkable creativity stretching until at Fairchild, and C. T. Sah, the manager a PhD in solid-state physics based on memory chips, arithmetic-unit chips, 2 charge carriers trapped at the surface Research to redouble it search for his departure for the start-up General of the solid-state physics department, the migration of ions in quartz. of the semiconductor that prevented calculator chips, and customizable- areas where the technology could Microelectronics in December 1963, began putting together a team to In October 1963 this Fairchild group electric fields from penetrating beneath logic chips without finding significant prove relevant to IBM, resulting in Wanlass explored the chemistry and understand the MOS structure and made a breakthrough discovery. Snow the surface. When Fairchild started customers for any of them. 1966 to the program’s reorientation physics of MOS structures, built MOS the silicon-silicon dioxide system in a began a project assuming that different its work, previous work on surface toward semiconductor memory. At integrated circuits, and considered systematic way. Moore’s main reason metals applied as a gate electrode over states usually included caveats about MOS Technology at IBM that time the typical division of how various MOS phenomena could for starting this team was to produce the silicon-dioxide layer might show the difficulties of reproducibility and labor in computers was for logic to be commercially exploited. Wanlass’s better bipolar transistors—Fairchild’s different levels of stability. Researchers that results were valid only for specific International Business Machines be implemented using some kind greatest technological contribution was main area of business. But this work typically evaporated aluminum onto cases. Deal developed a number of was another major contributor to of semiconductor technology and the invention of CMOS (complementary would also be expected to address the the silicon dioxide using a tungsten techniques to eliminate these surface MOS technology. Its research group for memory to employ some type MOS), which led to transistor circuits stability problems of MOS transistors. filament, but because of the extremely states at the interface between silicon at Yorktown Heights, New York, was of magnetic technology. Computer that consumed almost no power in Up to this time, the problems of high melting points of platinum and the oxide layer. He later detailed drawn to this technology as a way to memory was one area in which speed standby operation (see Figs. 1 and 2). MOS stability were so great—an MOS and tantalum, Snow instead used an various characteristics of the surface- begin work in planar silicon technology, was not necessarily at a premium; While the complexities of building transistor’s characteristics might vary electron-beam evaporator to apply these state charge—specifically showing the which previously had been the exclusive cost was also a large factor. Here is CMOS circuits were so great in the by over a hundred volts over time metals.