Confined ion beam cylinder sputtering: A new approach

Abstract

A new high rate sputter deposition technique is reported which employs axial projection of an ion beam into a negatively biased target cylinder. The resulting acute incident bombardment angle which occurs on the inner cylinder wall results in a high sputter yield as compared to other cathode sputter configurations. Calculations showed that near‐optimal argon ion incidence bombardment angles can be obtained with this technique. The resulting sputtered metal flux had a directional character and was projected radially inward from the cylinder walls and ‘‘downstream.’’ Rapid coating rates were observed on substrates placed at the approximate ‘‘focus’’ of deposition. Variations in the cylinder bias, the substrate bias, and the substrate–incident ion energy control were shown to modify the morphology of coatings during deposition. TEM showed that near‐amorphous or fine grain beryllium films were deposited as a function of substrate–incident argon ion flux (approximately 100 and 30 nm crystallites at 1000 eV at 0.2 and 0.5 mA/cm2, respectively) on single crystal NaCl substrates. Ion bombardment during sputter deposition provides a large number of nucleating sites causing numerous small crystallites during condensation of the metal.