Combined substrate polishing and biasing during hot-filament chemical vapor deposition of diamond on copper

Diamond deposition on copper is problematic mainly due to the poor affinity between copper and carbon. Therefore, it becomes necessary to pretreat the substrate surfaces prior to diamond deposition. Several surface pretreatme nts have been investigated, such as polishing using various abrasives and s ubstrate biasing. In this study, we report new results relating diamond nuc leation on copper substrates to a combination of surface polishing and bias ing pretreatments, The results show that the combined pretreatments give a higher nucleation density than the two individual treatments. It was found that an increase of 70% in the nucleation density was observed when the sur faces were polished with diamond paste and then negatively biased. Copper s urfaces polished with diamond powder and then biased displayed the highest nucleation density obtained. Raman spectroscopy revealed that after negativ ely biasing the substrate for 30 min, broad D- and G-bands of microcrystall ine graphite were present, which completely disappeared with subsequent dia mond growth, leaving behind a good-quality diamond film.