2020/06/04 by Movaffaq Kateb, Kateb, Movaffaq, Jón Tómas Guðmundsson +3
Engineering · Materials Science · #Metal and Thin Film Mechanics #Copper Interconnects and Reliability #Semiconductor materials and devices
paper · pdf · doi:10.48550/arxiv.2006.05813
We explore combination of high power impulse magnetron sputtering (HiPIMS)\nand substrate bias for the epitaxial growth of Cu film on Cu (111) substrate by\nmolecular dynamics simulation. A fully ionized deposition flux was used to\nrepresent the high ionization fraction in the HiPIMS process. To mimic\ndifferent substrate bias, we assumed the deposition flux with a flat energy\ndistribution in the low, moderate and high energy ranges. We also compared the\nresults of fully ionized flux with results assuming a completely neutral flux,\nin analogy with thermal evaporation. It is confirmed that in the low energy\nregime, HiPIMS presents a slightly smoother surface and more interface mixing\ncompared to that of thermal evaporation. In the moderate energy HiPIMS,\nhowever, an atomically smooth surface was obtained with a slight increase in\nthe interface mixing compared to low energy HiPIMS. In the high energy regime,\nHiPIMS presents severe interface mixing with a smooth surface but limited\ngrowth due to resputtering from the surface. The results also indicate that\nfewer crystal defects appear in the film for moderate energy HiPIMS. We\nattribute this behavior to the repetition frequency of collision events. In\nparticular high energy HiPIMS suffers from high repetition of collision events\nwhich does not allow reconstruction of the film. While in the low energy HiPIMS\nthere are not enough events to overcome island growth. At moderate energy,\ncollision events repeat in a manner that provides enough time for\nreconstruction which results in a smooth surface, fewer defects and limited\nintermixing.\n