Characteristics of Cu thin films on a glass substrate by partially ionized beam deposition at room temperature

Partially ionized beam deposition of Cu thin films onto glass at room temperature was carried out to fabricate laser mirrors with good structural and reflective properties. At a constant him thickness of 600 Angstrom, the grain size of as-grown Cu films increased with acceleration voltage. There was no indication of defects such as cracks and/or large pores in the film surface as shown in scanning electron microscopy images. R(ms) surface roughnesses of 600 Angstrom thick films were measured by atomic force microscopy images. R(ms) surface roughness increased when acceleration voltage increased from 0 to 2 kV, but decreased at 3 kV. R(ms) surface roughness of the film grown at 4 kV, however, increased. At the acceleration voltage of 3 kV, reflectance of the films increased with the film thickness until 600 Angstrom and decreased at 800 Angstrom. The reflectance results showed that the Cu films deposited at 3 kV had higher reflectance than that of others. Our results suggested that it is possible to grow Cu films with good structural and optical properties on glass substrates at room temperature by partially ionized beam deposition. Copper films showed greater reflectivity than aluminum films used for laser mirrors by 2%-7%. (C) 1996 American Vacuum Society.