Proportion Controlling Of Dopants Of Dualelement Films Which Deposited By Magnetron Sputtering And Characterization Of Their Microstructure And Mechanical Properties

A number of low content doped dual-element film which has the similar thickness and gradient changes of content was deposited by magnetron sputtering,and through the characterization of film content,morphology and mechanical properties,to clarify the size and morphological evolution of the low volume fraction phase in the dual-element film when the content growth,and explain the reason of the film mechanical properties changes.First,based on the sputtering yield model,a simulation method which can predicate film composition is presented in this thesis,and this method is verified by the experiment.The results show that: when the energy of Ar+ bombardment of the substrate is lower or much higher than the sputtering threshold of each component in the thin film,the calculated value by the simulation method of each component is very close to the measured;or the energy of Ar+ bombardment of the substrate between the sputtering threshold of several components,and the high sputtering threshold component as the absolute main phase,this method is also applicable.Finally,two groups of Cu/C and Si/Cu dual-element film which has suitable content and thickness had been obtained by this model,and this film was characterized by TEM and nanoindentation.The results show that: The main phase of carbon is amorphous in the Cu/C dual-element film.And the copper as fine nanocrystals embed in amorphous carbon with less number when the volume fraction of Cu is 3.0 vol.%,it will relieve the internal stress of amorphous carbon and soften the film.The number of Cu nanocrystals will increase if Cu content rise to 7.5 vol.%,and the softening effect are enhanced too.The hardness of the film are decreased from 22.2 GPa to 18.7 GPa.When the volume fraction of Cu are increased to 12.9 vol.%,the number of Cu nanocrystals increases rapidly and the grain size is grown up,it will form a microstructure of amorphous enclose nanocrystals.Strengthening effect is much greater than the softening effect because there is a substantial increase in the proportion of the phase boundary now.The hardness of the film enhance to 21.7 GPa.Continue to increase the volume fraction of Cu,Cu grains begin to grow together because the amorphous carbon is already not enough to separate the Cu grains completely.Vertical columnar structure is formed in the substrate direction and the maximum grain size is more than 20 nm.It reduces the phase boundary proportion and converts some phase boundary to grain boundary.Strengthening effect is weakened and the softening effect is enhanced.Mechanical properties of the film decrease again.The main phase of copper is grown with the columnar structure and in the direction of vertical the substrate.The low volume fraction of Si phase has two different microstructures,one is fine spherical amorphous nanoparticles and another is intermittent lamellar structure in some areas.The proportion and continuity of intermittent lamellar will improve if the Si content increase.When the volume fraction of Si increased from 6.4 vol.% to 10.6 vol.%,hardness and modulus of Si/Cu dual-element film are decreased respectively from 4.9 GPa and 200.0 GPa to 4.5 GPa and 176.6 GPa.Continuing to increase the volume fraction of Si,the film hardness enhances rapidly but the variation range of modulus is very small,the hardness has reached to 6.1 GPa when the Si content at the maximum,and the modulus is only 176.0 GPa.Therefore,the phase of Si can embrittle the Si/Cu dual-element film.