Sputter deposition biased

A second method of surface smoothing is to deposit a thick layer of SiOj and then a thin the layer by RIE or sputter etching. Because the sputter yield of the SiOj is greatest at an angle of 45°, the corners in the SiOj film etch quicker than the rest of the film and are therefore rounded by the etch process. With some deposition systems, for example, biased electron cyclotron resonance (ECR) plasma deposition, it is possible to deposit and etch concurrently, yielding a one-step process with a reduced deposition rate. ... 

Arc vapor deposition often involves coating 3D objects, and rotatable fixtures that allow deposition over the whole surface with a uniform angle-of-incidence of the depositing vapor flux are necessary. Often the fixture is biased to some voltage to allow sputter cleaning and energetic bombardment of the growing film. 

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