Effect of grain size and orientation on magnetron sputtering yield of tantalum

Abstract

The electron beam melting (EBM) technique was employed to prepare ultra-highly pure (99.999 wt%) Tantalum (Ta) cast ingot for application in chips. Subsequently, the Ta cast ingot were forged, rolled, and annealed with different durations to gain three different grain sizes (centimeter scale, 99.8 μm, and 36.7 μm). Sputtering experiments conducted under identical conditions revealed that the rolled target (36.7 μm) film deposition rate was increased by 60.6 % compared to the cast ingot target with a centimeter-scale grain size (columnar crystal). Ta targets with a fine grain size and homogeneous distribution demonstrate superior film deposition performance. The sputtering rate is directly related to the atomic packing density of grains. The (111)-oriented grains of BCC targets (Ta target) exhibit sputtering resistance, and the order of sputtering rate of Ta atoms was S₍₁₀₁₎ > S₍₀₀₁₎ > S₍₁₁₁₎.