TRAPPING AND LOW-ENERGY EXTRACTION OF PHOTODISSOCIATED IONS OF SF6

This paper describes a technique for spatially confining mass-selected ions and extracting them to a solid surface at low kinetic energy. Th is technique combines rf ion trapping with multiphoton ionization by a KrF excimer laser. SF5+ ions photodissociated from SF6 were separated from other ionic species and stored in the cylindrical ion trap cell for at least 100 ms. The stored ions were extracted onto the surface w ith low kinetic energies around 10 eV. This technique should be useful for studying surface reactions with mass-selected, state-specified, a nd very-low-kinetic-energy ions and for developing etching processes t hat can be used to control the surface structure of semiconductors on an atomic scale.