Evolution of microstructure of IGZO ceramic target during magnetron sputtering

In this study, influence of magnetron sputtering on indium gallium zinc oxide (IGZO) ceramic target was studied to improve its performance and utilization. Results indicated that state of the target such as target grain uniformity, micro defects, C element pollution, and secondary phase showed significant influence on magnetron sputtering process. Atoms located in small grains were easily bombarded out of IGZO target, and grains with slow sputtering rate protruded from target surface. Porous microstructure of IGZO ceramic created abnormal electric field of the target during sputtering, resulting in the poisoning of target. Moreover, more indium atoms were sputtered from the target, and the proportion of In after sputtering decreased by 0.62-0.97%. The difference in sputtering rates between secondary phase and main phase led to the formation of IGZO cladding layer with poor conductivity under the combined action of sputtering and re-sputtering. In sum, these findings may provide strong guidance for further improvement and performance enhancement of IGZO sputtering target.