Secondary ion emission from a GaAs single crystal upon bombardment with Bim+ cluster ions

Secondary-ion mass spectra and energy distributions upon bombarding a gallium arsenide single crystal using Bi m + ( m = 1–5) cluster ions with energies of 2–12 keV are investigated. The gallium cluster ion yield grew nonadditively with the number of atoms in the cluster projectiles. A quasi-thermal component found in the energy spectra of secondary Ga + and Ga 2 + ions is indicative of the occurrence of the thermal spike mode upon cluster ion bombardment. The quasi-thermal component in the yield of atomic Ga + ions upon bombardment with Bi 2 + –Bi 5 + –ions is 35–75%.