We report on the demonstration of a low emittance, high brightness ion source based on magneto-optically trapped neutral atoms. Our source has ion optical properties comparable to or better than those of the commonly used liquid metal ion source. In addition, it has several advantages that offer new possibilities, including high resolution ion microscopy with ion species tailored for specific applications, contamination-free ion milling, and nanoscale implantation of a variety of elements, either in large quantities, or one at a time, deterministically. Using laser-cooled Cr atoms, we create an ion beam with a normalized rms (root mean square) emittance of 6.0×10-7 mm mrad √MeV and approximately 0.25 pA of usable current, which with optimal apertures could yield a brightness as high as 2.25 A cm-2 sr-1 eV-1. These values of emittance and brightness show that, with suitable ion optics, an ion beam with a useful amount of current can be produced and focused to spot sizes of less than 1 nm.
Citation: Nano Letters
Pub Type: Journals
ion sources, laser cooling and trapping, focused ion beams, ion microscopy, emittance, brightness, ion implantation