Accession Number : ADP008066

Title :   Atomic Layer Epitaxy of Tungsten and Boron for Multilayer X-Ray Optics,

Corporate Author : BRIGHAM YOUNG UNIV PROVO UT

Personal Author(s) : Shurtleff, J.K. ; Phillips, J.

Report Date : 05 MAR 1992

Pagination or Media Count : 2

Abstract : The demand for high quality multilayer x-ray optics (MXOs) has increased as x-ray imaging applications have developed. MXOs must be uniform and smooth with precise periods. The period of the MXO determines the angle and wavelength of the x-ray which can be reflected. Current preparation of techniques are limited to a period of approximately 40 A. To reflect harder x-rays at near normal incidence, smaller periods must be achieved. We are investigating a new technique for producing MXOS. Atomic layer epitaxy (ALE) is a chemical vapor deposition (CVD) technique which can deposit a monolayer of atoms during each cycle of the deposition process, The total thickness of the deposited film is determined by the number of cycles and can be controlled to within a monolayer. ALE can also produce crystalline superlattice structures. Our theoretical calculations show that the x-ray reflectivity of a crystalline superlattice will be approximately twice as large as a similar amorphous multilayer. ALE can also deposit multilayers on large or figured substrates, since the reactants are gaseous and diffuse rapidly. This is not possible with current multilayer preparation techniques.

Descriptors :   *EPITAXIAL GROWTH, *OPTICS, *TUNGSTEN, *BORON, *X RAYS, *ATOMIC PROPERTIES, ANGLES, ATOMS, CHEMICALS, CYCLES, DEPOSITION, DEPOSITS, FILMS, LAYERS, NUMBERS, PREPARATION, QUALITY, REFLECTIVITY, STRUCTURES, SUBSTRATES, SUPERLATTICES, THICKNESS, UNIFORMS, VAPOR DEPOSITION, VAPORS, IMAGES, CRYSTAL STRUCTURE.

Subject Categories : Physical Chemistry
      Crystallography
      Nuclear Physics & Elementary Particle Physics
      Optics

Distribution Statement : APPROVED FOR PUBLIC RELEASE