Thinner Films Conduct Better Than Copper

If you need to move electrons from here to there, you turn to copper. This common element is an excellent conductor and is easily fabricated into wires and circuit board traces. But the situation changes when you get small: really, really small on a nanometer scale. That same copper shows increasing resistance, which means that more of the electrical signal is lost to heat. It could take more energy to power a smaller and denser device, which is just the opposite of what you want for miniature electronics. Researchers at Stanford led by Asir Intisar Khan in Eric Pop’s lab have been experimenting with a novel thin film scaled down to about 1.5 nanometers in thickness. They have found that as this film gets thinner, its conductivity increases, which is the opposite of how copper behaves. They started with a sapphire substrate and then applied a seed layer of niobium (Nb). They experimented with various thicknesses of this Nb layer, from 4 nm to 1.4 nm. This layer helped the following l ... Read full article.