Temperature of the Cathode as a Factor in the Sputtering Process

Abstract

Effect of high cathode temperatures on the rate of sputtering of metals.—Gold, platinum and nickel show an increase in the rate of sputtering in argon with increase in cathode temperature. The lower the sputtering voltage the more pronounced the effect. Films sputtered from a hot cathode show considerable initial aging, i.e., suffer less change in resistance on baking and show a more definite crystal structure than those from a cold cathode. While evidence is presented to show that the "explosion theory" of sputtering may have a certain basis of fact, especially as regards starting conditions, the results are, on the whole, consistent with the explanation of sputtering as essentially a vaporization process. The indications are, however, that ordinary evaporated films, even when produced under the same pressure as sputtered films, contain less gas, pointing to the excitation accompanying the discharge as an important factor in the process of gas occlusion in the films.