SUPPRESSION OF CONE FORMATION ON CARBON TARGET DURING SPUTTERING

The mechanism of cone formation on a carbon target in sputtering was investigated. Marked whisker growth was observed on the target surfaces of both graphite and glasslike carbon during sputtering when the target was not cooled sufficiently. This whisker growth causes significant cone formation on the target surface, which makes it difficult to perform sputter deposition at a gas pressure below 1 mTorr. On the other hand, cone formation was completely suppressed on the glasslike carbon target when target cooling was improved, which made it possible to perform sputtering at a gas pressure as low as 1x10(-4) Torr. This indicates that the use of the glasslike carbon target and cooling of the target during sputtering are effective for suppressing cone formation on the target.