Temperature dependence of the angular distribution of material sputtered from a CuPt alloy

CuPt targets were sputtered with 20 and 80 keV Ar+ ions at temperatures from -196 to +5500C, in order to study the interplay between radiation-triggered and thermal (Gibbsian) surface segregation of copper. Over the range -196 to +3000C, the dependence of flux composition on emission angle, and hence the surface segregation, did not change with temperature. Above + 3000C the flux composition was virtually independent of emission angle, but the copper concentration was very much enhanced over that of the target, implying that steady state conditions had not been reached. The surface of the irradiated, copper-depleted target was very rough and no conclusions could be reached with respect to segregation at these elevated temperatures. (orig.)