Deformation Direction and Curvature Control of Multilayer Thin Films Produced by Sputtering

IKAROS, a solar sail spacecraft launched in 2010, demonstrated that thin-film solar cells can generate electricity. During this demonstration, it was found that the cells became curved, which destabilized the attitude of the spacecraft. Therefore, this study focused on a sputtering deposition technique that generates internal stress during the formation of thin films. The objective of this study was to control the curvature of a multilayer film by sputtering with a pattern. The effect of sputtering on the thin film was analyzed through experiments and simulations, and it was clarified that the cause of shape non-reproducibility is sputtering-induced stress.