Wrapping graphene around wires may boost chip speeds

A series of Stanford-led experiments demonstrate that graphene may be able to replace tantalum nitride as a sheathing material for chip wires, to help electrons move through the copper wires more quickly. The scientists say that using graphene to wrap wires could allow transistors to exchange data faster than is currently possible and the advantages of using graphene could become even greater in the future, as transistors continue to reduce in size.

The protective layer isolates the copper from the silicon on the chip and also serves to conduct electricity. Its significance is great since it keeps the copper from migrating into the silicon transistors and rendering them non-functional. Graphene has several advantages for this kind of application: the scientists could use a layer eight times thinner than the industry-standard and get the same effect, and the graphene also acts as a barrier to prevent copper atoms from infiltrating the silicon. The Stanford experiment showed that graphene could perform this isolating role while also serving as an auxiliary conductor of electrons. Its structure allows electrons to move from one carbon atom to another, down the wire, while effectively containing the copper atoms within the copper wire. 

These major benefits allow this new wire technology to carry more data between transistors, speeding overall chip performance in the process. Looking at today's chips, these advantages are relatively mild - boosting wire speeds from 4 percent to 17 percent, depending on the length of the wire. But as transistors and wires continue to reduce in size, the benefits of the ultrathin yet conductive graphene isolator become greater. The Stanford engineers estimate that their technology could increase wire speeds by 30 percent in the next two generations.

Posted: Jun 18,2015 by Roni Peleg