The graphene-sheated copper wires enabled speed boosts of 4-17 percent, depending on the length of the wire, and the researchers believe this can be enhanced to up to 30 percent in future chips. Interestingly, the research shows the performance boost increases as the wires get smaller.
Here’s where Stanford’s research comes in. The reason the copper wires are traditionally wrapped in tantalum nitride is to ensure that copper doesn’t migrate into the surrounding area of the chip. One of the team’s findings was that the tantalum nitride layer is roughly 8x thicker than an equivalent layer of graphene that performs the same function. That’s important in and of itself, as it allows wires to be made thinner overall without actually changing the amount of copper (think of this as making a water pipe thinner by reducing the exterior diameter but leaving the interior diameter unchanged.The big problem however remains the volume production of graphene.
The second and arguably more important reason is that the graphene effectively acts as a secondary conduction path for the copper itself. Today, the effect is relatively modest — sheathing copper wires in graphene boosts speeds by 4-17% depending on the length of the wire. In future chips, however, the benefits could be more significant — wires might be up to 30% faster while still scaling to smaller sizes. Because wire delays have become one of the most significant performance limiters in modern semiconductor designs, increasing copper wire speeds could improve multiple aspects of chip design and power consumption.