VALENCE EXCITATION AND ESD OF CL+ IONS FROM THE CL SI(100) INTERFACE/

The threshold of Cl+ ion formation from the Cl/Si(100) interface due t o electronic excitation has been studied using surface mass spectromet ry incorporating a time-of-flight technique. Ionization of the Cl 3s l evel followed by valence band Auger decay is found to be an effective way of ion production. The low kinetic energy of the ions is interpret ed as due mainly to the screening of the surface Si+ which occurs on a time scale comparable with the desorption time of the Cl+ ions. Cl+ i on production is also observed at energies below the Cl 3s level with a low energy cut-off at 15 eV.