Sputter deposition with powder targets : an overview

To accommodate to the current trend to study chemically more complex materials, several strategies have been developed to increase the flexibility to deposit these materials by magnetron sputtering. Among these strategies, sputtering from loosely packed powders as a target material, takes a special place as it abandons the requirement of a high density target as a source. The low thermal conductivity, and the inherent presence of impurities, are the major disadvantages of powder targets, and are boundary conditions that always need to be considered when these targets are used. Nevertheless, the easiness to produce any target composition often overrules these disadvantages. Some fundamental aspects specific for these targets, such as sputter yield and angular distribution of the sputtered atoms, are discussed. The use of powder targets is compared to alternative methods to deposit complex thin films