Method and apparatus for reactive sputtering

Abstract From the Canadian patent

A reactive sputtering process is described for producing a thin film of sputtered material on a tubular substrate which may, for example, be a solar collector tube. Uniformity of the composition of the sputtered layer at all points at the same depth in the film is achieved by preventing the movement of reactive gases through which the sputtering has already then place, from one part of the zone of sputtering to another. In one way of achieving the result the reactive gas is swept from the zone of sputtering by entraining it in a gas stream flowing across the sputtering path. In an alternative way of achieving this result the rate of flow of reactive gas is finely controlled so that it is …