The beams can create tiny features in the lateral dimensions—length and width, but to create the next generation of nanometer-scale devices, the energetic ions must precisely control the features in the vertical dimension—depth. Now, researchers at the National Institute of Standards and Technology (NIST) have demonstrated that a standard ion-beam technique can be fine-tuned to make structures with depths controlled to within the diameter of a single silicon atom.

Above – nanofluidic staircase machined with subnanometer precision by a focused ion beam separates nanoparticles by size. The device is also a reference material to accurately measure nanoparticle size and compare it to optical brightness, which could aid in the quality control of consumer products. Credit: NIST