Desorption of Ga and As Atoms from GaAs Surface Induced by Slow Multiply Charged Ar Ions

A reaction on a semiconductor surface induced by the potential energy of slow multiply charged ions (MCIs) has been investigated. By using an Einzel-type ion decelerator, beams of slow MCIs ( Ar q +; q≤10) with an ion current of several tens of nanoamperes and with the kinetic energy (E k) of 30×q eV were produced. Irradiating a GaAs surface with the slow Ar q + induced the desorption of Ga and As atoms, and this desorption was almost independent of the E k but strongly dependent on the q; that is, on the potential energy (E p) of the Ar q +. The effect of E p on atom desorption was analyzed quantitatively in terms of a model based on the Coulomb repulsion between holes generated on the surface through neutralization of the MCIs.