Abstract
DC reactive sputtering of SiO2 films is performed using a new rotary cathode. The cathode is positioned at the center of the vacuum chamber used for deposition, so that the chamber is partitioned into a pre-sputtering zone and a deposition zone assisted by a partition block. When this new rotary cathode is used, the insulating film formed at the boundary between the eroded and uneroded areas on the target surface is removed. The insulating film mentioned above causes arcing during sputtering, but the new method suppresses arcing, and the electrical conductivity of the metallic cathode is increased. Consequently, the deposition rate is increased considerably during DC reactive sputtering.
This new method necessitates two separate zones in the vacuum chamber: a pre-sputtering zone and a deposition zone. Plasma of two types must be introduced into the two zones simultaneously. The ignition voltage and sputtering voltage in each zone are controlled according to the discharge gas pressure in each zone. Using this method, the deposition rate for SiO2 films can be increased to 4 nm/s, which is 2.5 times the conventional deposition rate.
