It’s also likely to be too expensive and difficult to integrate with existing silicon technology. Images: Heng Wu/Purdue Universityīut as we eventually discovered, the III-V approach has some fundamental physical limitations. The distance between each fin in the top image is in the tens of nanometers. The two transistors in the FinFET-based inverter contain finlike channels, which stand out from the plane of the wafer (top, one set of fins (in pink) from a bird’s-eye view bottom, an oblique view of another set). In fact, eight years ago, I wrote a feature for this magazine heralding the progress that had been made in constructing transistors with III-V channels. Building transistors with such channels could help engineers continue to make faster and more energy-efficient circuits, which would mean better computers, smartphones, and countless other gadgets for years to come.įor a long time, the excitement over alternative channels revolved around III-V materials, such as gallium arsenide, which are made from atoms that lie in the columns just to the left and right of silicon in the periodic table of elements. The idea is to replace the silicon there with a material that can move current at greater rates. The world’s leading-edge chipmakers are contemplating a change to the component at the very heart of the transistor-the current-carrying channel. But now, remarkably, the material is poised for a comeback.

Thanks to Moore’s Law, the transistor has delivered computers far beyond anything thought possible in the 1950s.ĭespite germanium’s starring role in the transistor’s early history, it was soon supplanted by silicon. The result was the first transistor-the amplifier and switch that was, arguably, the greatest invention of the 20th century. The flow of current through this configuration could be used to turn a small signal into a larger one. Nearly 70 years ago, two physicists at Bell Telephone Laboratories-John Bardeen and Walter Brattain-pressed two thin gold contacts into a slab of germanium and made a third contact on the bottom of the slab.

Silicon germanium transistor