Investigation of Al–Cr alloy targets sintered by various powder metallurgy methods and their particle generation behaviors in sputtering process

Abstract

Al–Cr–N films for tribological application are commonly prepared by sputtering on Al–Cr alloy targets in an Ar + N2 mixed atmosphere. Generally, a film is manufactured by co-sputtering on an Al and Cr target, which tends to produce an arbitrary composition. It is difficult to produce an alloy target with a high Al ratio by melting technology due to the formation of brittle intermetallic compound phases (IMCs). In this study, alloy targets were manufactured by various powder metallurgy methods, included hot pressing (HP), hot isostatic pressing (HIP), and low temperature novel forming (LTNF). The results showed that at higher temperature, HP targets were dense and developed a large amount of IMCs, giving the target poor mechanical properties. Cracking tended to occur on the target surface, and many particles were generated during the sputtering process. At a lower temperature, IMC formation was inhibited in these targets, but the density was poor. The HIP method produced similar results to those of HP. LTNF was developed to achieve a dense target free of IMCs. Furthermore, the sputtering performances of the alloy targets were verified. For the LTNF target, almost no arcing count was recorded, fewer particles were generated and better film uniformity was obtained. The target and sputtering characteristics of conventionally-made (HP and HIP) methods were less desirable.