CONDENSATION COEFFICIENTS OF SILVER, GOLD, AND COPPER IN VACUUM DEPOSITION

Abstract

A beam of atoms striking a substrate will in general not condense completely, but some of the incident atoms will re-evaporate. The condensation coefficient– denfined as the ratio of the number of atoms condensing to the total number incident on the substrate–has been determined for silver at substrate temperatures from −30 °C to 170 °C, and for gold and copper at temperatures from 25 °C to 165 °C. For silver at room temperature the condensation coefficient is found to be 0.936, which indicates 6.4% of the incident atoms are re-evaporated or diffusely reflected. By a simple graphical analysis of the results it is shown that the temperature below which complete condensation occurs is 200 °K for silver, 230 °K for gold, and 180 °K for copper.