Researchers at the National Institute of Standards and Technology (NIST) reportedly developed a new method of focusing a stream of ions into a point as small as one nanometer (one billionth of a meter). The approach that they have devised is very versatile and can be used with a wide range of ions tailored to a particular function. In nanotechnology, it is expected to carve smaller features on semiconductors than now are possible. Additionally, it can also produce images of nanoscale structures with finer resolution than currently possible with electron microscopes.
The NIST researchers point out that the current technology for both applications is problematic because the high energies needed to focus gallium for milling tasks end up burying small amounts in the sample and contaminating the material. Additionally, when gallium ions are used to collect images they inadvertently damage the sample because they are relatively heavy. With a different approach, the NIST team created a focused ion beam that generates a small cloud instead of a sharp metal point. They use a combination of magnetic fields and laser light to trap and cool the atoms to very low temperatature. Then another laser ionizes the atoms and focuses them into a small beam of ions. The NIST researchers have called the device Magneto-Optical Trap Ion Source (MOTIS). The initial tests used chromium atoms. The team expects that other atoms could also be used. NIST News Release