Secondary ion yield changes in Si and GaAs due to topography changes during O+2 or Cs+ ion bombardment

Changes in secondary ion yields of matrix and dopant species have been correlated with changes in surface topography during O+2 bombardment of Si and GaAs. In Si, profiles were measured in (100) wafers at 6‐ and 8‐keV impact energy. At 6 keV, a yield increase of about 70% occurred for Si+ over a depth range of 2.5 to 3.5 μm, with changes in other species ranging from a decrease of ∼20% for Si+3 to an increase of more than 25% for O+. The development of a rippled surface topography was observed in scanning electron micrographs over the same depth range. Similar effects occurred over a 3–5 μm depth range for 8‐keV ions, and in (111) silicon at a depth of 3 to 4 μm for 6‐keV ions. No differences were noted between p‐ and n‐type silicon, or implanted and unimplanted silicon. In GaAs, profiles were measured in (100) wafers at 2.5‐, 5.5‐, and 8‐keV impact energies. At 8 keV, a yield increase of about 70% was found for GaO+ in the range 0.6–1.0 μm, with smaller changes for other matrix species. At 5.5 keV, simil...