Many of the most important advances in science occur at a scale so miniscule that their effects are invisible to the unaided eye. That’s why IBM scientists create unusual visual aids to help people understand their work. Years ago, IBM physicist Don Eigler demonstrated the ability to build structures at the atomic level by spelling out IBM with individual atoms. Well, a team of researchers at our Zurich lab has done Eigler one better. They have produced a work of art at the nano scale–carving a replica of the famous Matterhorn peak that’s just 25 nanometers high.
Urs Duerig, one of the scientists involved in the project and a mountain climber in his leisure time, explains the choice: “I always had the dream of mimicking the ancient Egyptians and chiseling stones, making something beautiful, so I said, ‘Let’s try to do a work of art.’” He chose the Matterhorn as the subject for obvious reasons. To avoid being labeled provincial, the team also carved a tiny elliptical replica of the world. It measures 22 by 11 micrometers. More than 1000 copies would fit on a grain of salt.
Enough fun for the non-scientists, though. The team’s handiwork illustrates an important scientific achievement. For the nanotechnology revolution to fulfill its potential, scientists and engineers need tools and techniques for creating structures at the nano scale for use in electronics, medicine, and life sciences–devices that can be used to make the world work smarter and better. The Zurich team’s carvings demonstrate a breakthrough they have achieved in the field of scanning probe lithography. “It’s a completely new method for creating structures at the nano scale,” says IBM Zurich researcher Armin Knoll.
They use a sharp cutting tool, called a nanotip, to carve patterns in semiconductor materials. The tip, which is just 50-atoms across at its point, is heated to between 300 and 700 degrees Celsius to to make it possible to evaporate the material without so much force that the nanotip wears out. Think of it as a miniature milling machine.
Such tips have been used to carve materials before, but the team produced several significant inventions, including their method of positioning the tip, the materials they used, and the ability to carve the material in three dimensions at such a fine resolution. The Zurich team, primarily physicists, worked with chemists at IBM’s Almaden lab to produce the materials they use–molecular glass for the Matterhorn and a heat responsive polymer for the globe.
Their method will make the process of creating nano structures much cheaper than existing methods for university scientists and corporate researchers. “We can make nano science available to a large audience,” says Knoll.
The team faces some significant challenges. Their next task is to figure out how to scale up production. It took just 2 minutes and 23 seconds to carve the globe, but that’s a lot of time when you apply the technique to the mass production of devices. So the team is developing techniques for using several thousand tips in parallel.
That will be an important step toward turning the promise of nanotechnology into reality.