Mechanical Stresses in Vacuum Deposited Films of Ag, MgF 2 and ZnS

• Published in: Japanese Journal of Applied Physics Vol. 3; no. S1; p. 340
• Main Authors: Kinosita, Koreo, Nakamizo, Kozo, Maki, Kunisuke, Onuki, Kota, Takeuchi, Kyoko
• Format: Journal Article
• Language: English
• Published: 01.01.1964
• ISSN: 0021-4922; 1347-4065
• DOI: 10.7567/JJAPS.1S1.340

The film material is deposited at 10 -5 Torr onto a thin strip of mica clamped at one end, and the stress within the film is determined by observation of the bending of the strip. The total stress S and the mean stress per unit cross section of the film σ are given as functions of the film thickness d up to a few thousands of ångströms taking the deposition rate as a parameter. The stress in MgF 2 films is tensile, σ assuming a maximum at a thickness (≈1,000 Å) which depends on the deposition rate. ZnS films deposited slowly (1–3 Å/s) exhibit tensile stress. If deposited at faster rates (8–17 Å/s) they show compressive stress in the range d <1,200 Å; above this thickness the stress becomes tensile. Silver films exhibit tensile stress, and σ assumes a maximum in the thickness range 100 to 200 Å where the crystallites coalesce to form a coherent film.