In a what could only be described as a dismally attended talk at Clark House, Mody provided valuable insights into the progression of silicon-based technologies, specifically that of computer chips. His talk, titled "The Long Arm of Moore's Law," used Moore's Law as a jumping-off point for analyzing the formation of communities of scientists and engineers around a common technique, material, goal, institution or discipline.
Researchers and industry players in silicon-based technologies have long placed strong emphasis on Moore's Law, which is attributed to Gordon E. Moore, a co-founder of Intel Corporation. The result of an empirical observation made in 1965, Moore's Law states that the number of transistors on an integrated circuit for minimum component cost doubles every 24 months.
Moore's Law has come to serve as an industry standard for companies as the technology progressed. Not only serving as a measure of technological and scientific progress, the law also takes into account the costs of materials and production.
Mody began with a brief overview of present day uses of silicon technologies. Referencing materials that he had handed out at the beginning of the lecture containing various diagrams and photos, Mody showed a diagram of a basic transistor. These can be found in their thousands, even millions, in commonplace household items like computers.
Cell phones and other digital appliances, as well as the Internet, rely on monolithic integrated circuits, also known as silicon chips.
Although computer chips keep shrinking and new technology is continually being marketed, the uses of silicon will eventually approach a physical limit, due to the fact that a layer of silicon dioxide must be at least four to five atoms thick to be an insulator. Eventually, a point would be reached at which the physical distance between transistors would undermine a chip's efficacy. Another concern lies in dealing with the heat that would be generated by a highly concentrated group of transistors, liable to damage the chip.
As these limitations of silicon technologies becomes more apparent, the industries concerned have made efforts to look into different materials and techniques in order to extend the application of Moore's Law to computer chips beyond the limits of silicon.
Currently, possible alternatives to silicon integrated circuits do exist. These are in fact quite numerous, ranging from molecular electronics to microfabrication (which may eventually become nanofabrication).
Josephson computing for the production of quantam-mechanical circuits and probe microscopy are also considered viable options. In particular, Mody drew the audience's attention to pictures of the first avatar of molecular electronics, and dendrites of germanium in single crystals as examples of the current and past efforts to find an effective alternative to silicon.He also presented some of the historical developments of computer chip technology, referencing diagrams comparing chips by Westinghouse, who in the 1950s wanted to become a microelectronics company, with little success, and by Fairchild Semiconductor, which originally had a large lead in the industry.
Also referenced was research conducted by Mark Reed of Yale University and Jim Tour of Rice University. Reed and Tour teamed up in 1999 and did some experiments, reporting that phenylene ethynylene molecules show negative differential resistance. They had discovered that when molecules were placed between a pair of electrodes, their conductivity decreased as electric voltage rose.
This was the reverse of what most molecules usually do, becoming more conductive when subjected to higher voltage. This property could be utilized in the creation of electric switches and as an alternative to silicon transistors.
Mody explained, however, that it was difficult for these alternatives to break into Silicon Valley and make headway as they represent a departure from the traditional techniques, instruments and materials upon which the current transistor community is based.