Self sputtering on cobalt single crystals

Sputtering yields have been measured, using the weight loss method, on cobalt single crystals irradiated with 100 keV Co+ ions. Results have been obtained as a function of temperature in the range 200C to 4500C, covering both the hcp and the fcc phase, and as a function of fluence in the range 1020-1023 m-2. In addition polycrystalline sputtering yields were measured over the entire temperature range. Sputtering yields under channeling conditions were, as expected, significantly lower than the polycrystalline yields. Unexpectedly, however, the channeled sputtering yield was constant over the entire temperature range, and therefore independent of the crystal structure. The high fluence results could not be interpreted within the framework of the transparency model, which was only applicable at low fluences. The applied fluence is therefore an essential parameter in single crystal sputtering. RBS analyses show that the fluence dependence of the sputtering yield is largely due to the particular radiation damage microstructure formed during the sputtering process. (orig.)