SURFACE-COMPOSITIONAL AND ANGULAR-DISTRIBUTIONS DURING CU-PT SPUTTERING

Under 1 keV Ar ion bombardment of Cu-Pt alloys at high fluence and low temperature, the depletion degree of the segregating species at the s econd surface layer, and the normalized sputtering yield ratios (non-s egregating species/segregating species) in the near-normal direction ( 15 degrees) and at oblique angle (75 degrees), have been estimated by an improved kinetic BIGS (bombardment-induced Gibbsian segregation) mo del. For the bombarded Cu-Pt alloys, calculations show that the deplet ion degree of the segregating species at the second surface layer is s mall when its bulk composition equals the extreme value, but this depl etion degree becomes large when its bulk composition equals the interm ediate value. Furthermore, the difference of the normalized sputtering yield ratio between 15 degrees and 75 degrees is small when the bulk composition of the segregating species equals the extreme value, but t his difference becomes large when that of the segregating species equa ls the intermediate value.