Preparation of Ti-Al-Si spattering target by pulse current pressure sintering

We investigated the relationships between sintering conditions of TiAlSi mixed powder and microstructures of the sintered compacts for the purpose of fabricating large sputtering targets (such as 160mm × 100 mm). The pulse current pressure sintering (PCPS) method was employed in order to consolidate the mixed powders consisting of Ti50: Al40: Si10 (atomic %). Ti ₅₀Al₄₀Si₁₀ compacts were made under conditions of various pressures (49-98 MPa) and temperatures (773 K ∼ 873 K). When the sintering temperature was 833 K or higher, Al-Si liquid oozed out during the process. When the sintering temperature was lower than 833 K, many micro pores have been formed in the sintered compact. When the sintering pressure was high, the relative density of the compact was higher and metallic compounds have formed at the interface between Ti and Al/Si. Relative density of 97% was obtained from the compact sintered at 823 K under the pressure of 60 MPa. Water quenching test revealed that this sintered compact had high resistance to thermal shock due to the formation of metallic compounds. Applying this sintering condition, disk compacts of Φ190mm×8 mm were successfully obtained and 160 mm × 100 mm rectangular sputtering targets were fabricated from these disks. Then we investigated the microstructure and mechanical properties of Ti-Al-Si-N films deposited from the rectangular targets to confirm whether the targets are useful for sputtering. The targets were sputtered in a mixture of argon and nitrogen using an r.f. sputtering apparatus of facing target-type sputtering. The Ti-Al-Si-N films obtained the highest hardness of 43 GPa when they were deposited at 573 K without substrate bias. The hardness of the films was ∼ 20% higher than that of Ti-Al-N films. These results indicate that the Ti₅₀Al₄₀Si₁₀ compacts sintered by PCPS are useful for sputtering targets.