Sputtering of the most volatile solids: the solid hydrogens

Abstract Electronic sputtering of the three stable hydrogenic solids, H 2 , HD and D 2 by keV hydrogen and deuterium ions has been studied at the low-temperature setup at Riso. The yield of the sputtered particles has been determined for hydrogenic films of thicknesses ranging from 0.1 × 10 18 up to 10 × 10 18 molecules/cm 2 and for 4–10 keV H + , H 2 + , H 3 + and D 3 + ions. The yield increases with decreasing film thickness for solid hydrogen as well as for deuterium. This behavior agrees with the trend observed for other volatile gases. For thick films the yield decreases to a constant value. This thick-film yield can be approximated fairly well by a quadratic function of the stopping power except for a somewhat steeper dependence for proton-bombarded deuterium. The yield increases strongly with decreasing sublimation energy from one isotope to another. No existing theory can account for the dependence of the yield on the electronic stopping power as well as the sublimation energy.