Development and Modeling of Cylindrically Shaped Multilayer X-Ray Reflectors

Chemical vapor deposited nickel thin films are used for the controlled bending of silicon wafers with (110) surface orientation into cylindrical shapes to be used as substrates of multilayer x-ray reflectors. A model is proposed to describe, and to predict the bending of the nickel silicon structure. The elastic properties and the intrinsic stress of the nickel film on silicon have been determined by a least squares fit of the experimental data. Surface topography of the bent nickel/silicon structure was characterized for its global features, waviness, and roughness. Deviation of the global shape from an ideal cylindrical surface, and structure surface waviness are the two major factors affecting the surface quality. Multilayer structures have been deposited on bent silicon wafers to produce prototype cylindrical x-ray reflectors.