Beam-induced lattice disorder in channeling experiments on Si and Ge

The disorder produced by 0.3-MeV D+ random bombardment in Si and Ge crystal targets has been investigated with 1.5-MeV D+ channeling measurements. An increase of about 30–50% in the 〈111〉- and 〈110〉-aligned yields of Ge samples has been found after a bombardment with a dose of 200–300 μC/cm2. No significant increase was observed in bombarded Si samples. Detailed angular scans suggest a ``spread-out'' distribution of defects imbedded in the lattice structure.