The Research Of Al₂O₃ Film Prepared By Twin Mag High Pulsed Power Magnetron Sputtering

As a material being widely applied in the film field,Alumina possesses good mechanical properties.In this paper,alumina film is prepared by twin-mag high power pulsed magnetron sputtering technology(Twin-mag HPPMS).SEM and XRD was taken advantage of to analyze the microstructure and the phase composition of the film.The mechanical performance of the film containing film-substrate cohesion,nano hardness and Young Modulus has been studied. The discharge characteristics of the Twin-mag HPPMS has been studied.Meanwhile,taking advantage of mass spectrometer,the plasma induced by the Twin-mag HPPMS has been monitored and analyzed.The result of discharge characteristics shows that,with the oxygen flow increasing,the target current rises,while the oxygen flow reaches 12 sccm,the current begins to fall.With the work voltage and pressure increasing,the target current shows a upward trend,and the increase of voltage can lead to a significant rise of the target current.The effect of the pulse length is not obvious on the target current,while the increasing of pulse frequency shows no impact on target current.The analysis of the plasma shows that, with the sputtering power increasing,the Al ions amount increases significantly,while the Ar ion amount changes little,and the O ion amount climbs up and then decline.With the oxygen flow increasing,the amount of Al ion decreases, both the O and Ar ion amount first increase then decrease.With the work pressure increasing, the amount of Al and Ar ion decrease,yet the amount of O ion increases.The analysis of micro-morphology and phase separation reveals that,with the oxygen flow increasing,the deposition rate decreases and the particles scattering on the film becoming more.-50 V bias voltage applied to the substrate,the deposition rate and density of the film increases.When the substrate temperature reaches550℃,the bias voltage is-50 V and the oxygen flow is 8sccm or 10 sccm,the γ-Al2O3 appears in the films,which means that it is partly crystallized.The test of mechanical performance indicates that,when the substrate temperature reaches 450 and 550℃,the spalling pattern of the films is compression like.The substrate temperature descending to the 300℃ and room temperature,the spalling pattern transforms to flexion like,implying a increase of the adhesion between the film and substrate.With oxygen flow increasing,the adhesion weaken due to the increase of the defects caused by the decreased deposition rate.A improvein the substrate temperature will increase the internal stress which contributes to a higher nano hardness and Young modulus.When the oxygen flow reaches 8sccm and10 sccm with the substrate temperature being 550℃,the γ-Al2O3 comes to appear in the film,resulting in a significant increase of the nano hardness and Young modulus.On the oxygen flow reaching 12 sccm,the phase of the film turns into amorphous,and the thickness of the film decreases sharply,causing the nano hardness and Young modulus being the minimum.