Sputtering Yield of Germanium in Rare Gases

摘要

Sputtering yields of germanium bombarded by Xe+, Kr+, A+, Ne+, and He+‐ions under normal incidence at energies up to 400 ev have been determined. Yield vs ion energy curves consist of three parts; (1) a low‐energy tail (possibly caused by a process of stepwise sputtering), (2) a region in which yield rises proportionally with ion energy, and above ion velocities of ∼3×106 cm/sec, (3) a region in which the yield rises less than proportionally with ion energy. The slope in the proportional region is largely determined by the energy transfer factor, η=4m1m2/ (m1+m2)2. Surprisingly, the ``cut in'''' energies do not follow V0∼H/η (H=heat of sublimation) but are found to be much lower than expected for the lighter gases. The empirical result, V0∼H(m1)½/η (m1=atomic weight of ion), is not yet understood.