AVS 51st International Symposium
    Thin Films Wednesday Sessions
       Session TF-WeM

Paper TF-WeM2
Determining Physical and Chemical Properties of Sputtered Uranium and Thorium Thin Films Useful as Extreme Ultraviolet Reflectors

Wednesday, November 17, 2004, 8:40 am, Room 303C

Session: Optical Thin Films
Presenter: R.W.L. Larsen, Provo High School
Authors: R.W.L. Larsen, Provo High School
D.D. Allred, Brigham Young University
Correspondent: Click to Email
As applications for extreme ultraviolet radiation have been identified, the demand for better optics has also increased. Recently, sputtered thin films containing uranium and thorium have been shown to produce the highest low-angle reflectors for portions of the EUV/soft x rays. For more progress to be made in this area optical constants needed to be obtained. In addition, optical properties need to be assigned to specific compounds and structures. The purpose of this project was to determine the composition, density, lattice structure, and roughness of these sputtered uranium and thorium thin films and their oxides and nitrides via TEM, XPS, AFM and to relate these structural effects to the reflectance of the thin films. We have found that the thorium samples oxidize more slowly in air than uranium so we can talk about the reflection of these films being a mixture of thorium and thorium oxide. Sputtered uranium on the other hand quickly becomes uranium dioxide which is moderately stable for periods of months. Whereas the sputtered uranium nitride samples are uranium mononitride only in the bulk and their surfaces become oxidized.