Introduction to special issue

Looking Beyond Silicon

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Science  26 Mar 2010:
Vol. 327, Issue 5973, pp. 1595
DOI: 10.1126/science.327.5973.1595

Silicon-based electronics have been the mainstay of the industry for several decades, a veritable powerhouse of the economy, driving technological breakthroughs that affect virtually all aspects of everyday life. Devices have gotten smaller, faster, more efficient, more powerful, and cheaper. However, the size of transistors—the building blocks of electronics—is approaching the limits of what can be done on a large-scale industrial basis. Has the time come when a replacement for silicon can no longer be avoided? If we look beyond raw processing power, might there be a future for silicon if it is given new capabilities?

On page 1600, Theis and Solomon set the agenda, describing the limits that silicon transistors have reached. They outline some of the different approaches being taken in developing a new transistor, still based on silicon but involving clever redesign and engineering of the basic structure. Summing up, they acknowledge that it may well be a materials issue—whether it is pushing the capabilities of silicon farther or developing new materials altogether.

Moving away from silicon, Takagi and Hwang (p. 1601) look at the richness of the electronic phases and enhanced functionality afforded by transition metal oxides. The properties of these strongly correlated electron systems can be dramatically affected by small changes in applied voltage or magnetic field, and can be used as memory storage or active devices.

Rogers and co-workers (p. 1603) review developments in making the electronics wearable or more transportable through a combination of flexiblilty, bendability, or stretchiness obtained by integrating inorganic and organic materials with suitable substrates. A recently published paper by Viventi et al. in Science Translational Medicine describes a method of using flexible electronics to measure the patterns of a beating heart.

Finally, Mannhart and Schlom (p. 1607) review the developments made with oxide interfaces. The junction of two insulating materials has been found to exhibit a vast array of different properties—metallic, superconducting, and magnetic—with the effects being tunable and devices scribable with an electric field. Mastering control over the interface properties is a formidable challenge, but doing so will offer unforeseen opportunities for technology and device function.

In a pair of News stories, Service (p. 1596) discusses an impending crisis in supplies of rare-earth elements and other materials vital to novel electronics and energy technologies and (p. 1598) describes advances in nitride semiconductors: materials that hold promise for fast-switching, heat-tolerant transistors, compact chemical sensors, and high-performance solar cells. Science Careers supplements the section with an online profile of a young British researcher working on nanoscale structures in gallium nitride.

Materials lie at the heart of all electronic devices. With the wide array of tricks used to coax silicon to do more and the wide range of new materials finding their way into electronic devices, the future looks to be more promising than the technology, gadgetry, and functionality we have seen thus far.

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