Ion emission and electric field characteristics in the liquid metal ion source with a new suppressor electrode

The liquid metal ion sources (LMIS) in focused ion beam (FIB) system have many advantages of high current density, high brightness and low ion energy spread. There are two electrodes being emitter and extractor for field ion emission in LMIS. But several LMIS have a new electrode called the suppressor. Characteristics of LMIS with a suppressor are investigated in terms of the electric field change due to the suppressor. The threshold and extinguishing voltages are investigated under the varying a suppressor voltage for a specified source voltage, and also current–voltage (I–V) characteristics have been observed in terms of the voltage difference between the source and extractor for the various suppressor voltages. It is found that the emission current decreases as the suppressor voltage increases since the increase in the suppressor voltage reduces the electric field. It is also noted that the threshold and extinguishing voltages are increased as the suppressor voltage increases.