A Semiconductor Better Than Silicon

MIT researchers say cubic boron arsenide is the best semiconductor material ever found, and 

maybe the best possible one. Credit: Christine Daniloff, MIT

Researchers from MIT and elsewhere have found a material that can perform much better than silicon. The next step is finding practical and economic ways to manufacture it.

Silicon is one of the most plentiful elements on Earth, and in its pure form, the semiconductor material has become the foundation of much of modern technology, including microelectronic computer chips and solar cells. However, silicon’s properties as a semiconductor are actually far from ideal.

One reason is that although silicon allows electrons to readily flow through its structure, it is much less accommodating to “holes” — electrons’ positively charged counterparts —and harnessing both is crucial for particular types of devices. 

Furthermore, silicon does a poor job of transporting heat, which contributes to the frequent overheating problems and pricey cooling systems in computers.

Now, a team of scientists from MIT, the University of Houston, and other institutions has carried out experiments showing that a material called cubic boron arsenide overcomes both of these limitations. 

In addition to providing high mobility to both electrons and holes, it has excellent thermal conductivity. It is the best semiconductor material ever found, and maybe the best possible one, according to the researchers.

Cubic boron arsenide has so far only been made and tested in small, lab-scale batches that are not uniform. In fact, in order to test small regions within the material, the scientists had to use special methods originally developed by former MIT postdoc Bai Song. 

More work will be needed to determine whether cubic boron arsenide can be made in a practical, economical form, much less replace the ubiquitous silicon. But even in the near future, the researchers say, the material could find some uses where its unique properties would make a significant difference.  READ MORE...