Presented at RSD2011: International Conference on Reactive Sputtering Deposition, December 8-9, 2011 Linköping, Sweden.
Bipolar pulsed reactive sputtering is a useful technique for deposition of dielectric films like Al2O3. The power balance of both magnetrons is important, as it can influence both the film thickness homogeneity of and film composition.
Two two-inch magnetrons have been used with Al targets in Ar/O2 gas mixture for reactive bipolar pulsing using a MAGPULS BP 1000/100/200 unit.
The device was operated in two regimes, called high-frequency and HIPIMS. This work focuses on the balance of power delivered to both magnetrons. In both regimes, higher current was observed in one magnetron with symmetrical pulsing due to slight difference between the magnetrons in the magnetic field strength. The resulting unequal power dissipation can be compensated by unequal ratio of on-times. However, modification of oxygen partial pressure changes the power balance again.
Working in the transition mode resulted in some negative feedback on the power dissipation.