Comparative Study on Residual Stress of Cubic Boron Nitride Films Deposited Using DC and RF Sputtering Sources

In the sputter deposition of cubic boron nitride (cBN) films using a boron carbide (B₄C) target, the difference in the residual stress of the deposited cBN films was investigated when deposition was performed by RF sputtering and DC sputtering. The threshold bias voltage required to form the cBN phase was − 100 V for RF sputtering, significantly lower than − 220 V for DC sputtering, attributed to the ion density of the RF plasma being larger than that of the DC plasma at a deposition pressure of 2 mTorr. As a result of comparing the residual stress of the cBN thin films deposited under each cBN deposition condition, the residual stress generated in cBN films deposited by RF sputtering was lower than that of DC sputtering due to the relatively low bias voltage for cBN formation. Thus, it can be concluded that the RF plasma is preferable in terms of the lower residual stress of cBN compared with the DC plasma. Graphical Abstract: [Figure not available: see fulltext.].