Investigation of Gas Phase Ions with a Quadrupole SIMS Instrument

SIMS instruments using a quadrupole mass spectrometer are usually provided with an electrostatic spectrometer in order to avoid degradation of the mass resolution due to energetic sputtered ions. In such an instrument, it is possible to study the energy distribution of sputtered ions by keeping the potentials applied to the electrostatic analyzer and to the extraction electrode constant and varying the specimen voltage. This approach was used by WHATLEY and WITTRY [1] to study the energy distribution of positive ions from group III and group VI elements in III-V semiconductors.