Since its invention in the early 1960s, engineers have fought to improve the design and function of the silicon chip. The building blocks of modern computing, each chip has a circuit etched into its silicon crystal surface. These intricate circuits conduct electricity, switching it on and off to produce a series of ones and zeros. The code can then be used to represent pictures, music and even movies in digital form.
Chipmakers have battled for fifty years to boost their chips power, all the while shrinking them in size. As our demand for smaller devices grows, could the solution lie in a radical move away from silicon?
For the first time ever, engineers may have found a way to mass-produce the world’s smallest chip. Stanford researchers have been exploring new materials to replace silicon. Measuring just 3 atoms thick, the new materials are much thinner and conduct electricity much more efficiently.
Following the discovery of graphene in 2004, engineers have hunted for similar crystals to turn into tiny circuits. A single carbon atom thick, graphene is a great electrical conductor. Discovering graphene proved remarkably low-tech, with engineers using scotch tape to peel away individual layers of the material. However, this method is no good for turning ultra-thin crystals into next-generation electronics.
Led by Eric Pop, an Associate Professor of electrical engineering, the engineers have found a way to make 2D devices. Their ultra-thin chips would be both transparent and flexible. These features could pave the way for windscreen displays in cars and monitors built into windows.
The material uses a single layer of the element ‘molybdenum’ sandwiched between two layers of sulphur. Each is just one atom thick. To turn this into a chip, the team had to produce a crystal the size of a thumbnail; 25 million times as wide as it is thick. To put this in perspective, that’s like making a sheet of paper 33 square kilometres in size.
Kirby Smithe is a graduate student in Pop’s lab who achieved this feat by adapting an existing manufacturing process. The process incinerates minuscule amounts of sulphur and molybdenum, vaporising the atoms. The airborne atoms then settle as a fine crystalline layer onto a glass or silicon ‘handle’.
Researcher Saurabh Suryavanshi then set about analysing the new crystal. By crafting accurate computer models of it, he could predict exactly how it would behave in a circuit.
Unimaginably tiny artwork
During chip manufacturing, circuits are etched into the conductive material. To show off the new material, the team instead etched tiny artworks into their prototype. Inspired by 2008’s carbon nanotube ‘Nanobama’, they even carved replicas of the recent US presidential runners.
Speaking of their subject choice, Pop said: “Many people are interested in electronics because the technology is useful. But we hope nanotrump and nanoclinton can broaden the interest in research. Perhaps seeing portraits etched into a three-atom-thick canvas will inspire future researchers in ways we can’t even imagine yet.”