Deposited profiles and homogeneous alloys from a hexagonal array of point sources

Abstract

Deposition profiles calculated for a hexagonal array of point sources were used to determine the optimum spacing of components in composite sputtering targets. The results showed that smooth deposit‐thickness profiles and homogeneous alloys could be expected for a point spacing of one‐half the source‐to‐substrate distance and that deposit‐thickness variations had nearly the same spacing dependence as had been calculated earlier for parallel strip sources. A Ag‐0.5 at.% Pu sputter deposit made from such a hexagonal‐array composite target was found indeed to be homogeneous by autoradiographic analysis of the Pu distribution in the deposit. The results for both point and strip sources suggest that vapor deposition will homogenize any inhomogeneous composite source if the spacing of the inhomogeneity is less than one‐half the source‐to‐substrate distance. Thus, vapor deposition can be used to chemically homogenize alloys.