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Within the next few years, high-performance chips containing as many as 0.5 billion transistors on a single chip will be produced. These advanced chips may contain up to 10,000 m of on-chip wiring connecting the individual devices with each other and with the outside world. However, such increased device and wiring densities cannot be achieved with currently used materials. The search is now on for materials that can replace silicon dioxide as the insulator in these future devices. But despite a bewildering number of candidate materials under investigation, a clear winner has yet to emerge.

In a typical microchip, layers of copper interconnect wiring are separated by a dielectric insulator, traditionally silicon dioxide (see the figure). Both the resistance of the metal and the capacitance of the insulator increase markedly as the wiring dimensions and pitch decrease, resulting in crosstalk and capacitative coupling …