Ultra-small integrated circuits have revolutionized mobile phones, home appliances, cars, and other everyday technologies. To further miniaturize electronics and enable advanced functions, circuits must be reliably fabricated in three dimensions. Achieving ultrafine 3-D shape control by etching into silicon is difficult, because even atomic-scale damage reduces device performance. Researchers at Nara Institute of Science and Technology (NAIST) have published a new study in Crystal Growth and Design in which they etched silicon to adopt the shape of atomically smooth pyramids. Coating these silicon pyramids with a thin layer of iron imparted magnetic properties that until now were only theoretical.