Since the invention of the MOSFET transistor sixty years ago, which is based on the semiconductor silicon, this chemical element has been an integral part of modern life. Silicon is readily available, cheap and has ideal electrical properties, but it also has an important disadvantage: it is very brittle and therefore breaks easily. This can become a problem if you want to use silicon to make microsystems, i.e. mechanical devices only a few micrometers in size, such as acceleration sensors in modern mobile phones.
At ETH Zurich, a team led by Jeffrey Wheeler, Senior Scientist in the Laboratory of Nanometallurgy, together with colleagues from the Laboratory for the Mechanics of Materials and Nanostructures at the Empa Materials Research Institute, has shown that under certain conditions silicon can be much more resistant and ductile than previously thought. In order to understand how the smallest structures of silicon can deform, Wheeler took a closer look at a widely used manufacturing method: the focused ion beam. Such a beam of charged particles can very effectively mill desired shapes into a silicon wafer, but it also leaves behind distinct traces in the form of surface damage and defects that make the material more easily broken.