X-ray optical multilayers: Microstructure limits on reflectivity at ultra-short periods
- Lawrence Berkeley National Lab., CA (United States)
- Lawrence Berkeley National Lab., CA (United States). Materials Sciences Div.
Multilayer X-ray mirrors of W and B{sub 4}C with period from 50 {angstrom} down to 5 {angstrom}, of interest as linear polarizers for soft X-rays, have been studied by X-ray diffraction and high-resolution transmission electron microscopy (HRTEM). Over this region soft X-ray reflectivity falls from 80% to 4% of the theoretical value. Hard X-ray reflectivity also falls dramatically, but the multilayers still show reflectivity for periods as small as d = 4.7 {angstrom}. The interface width (representing both roughness and interdiffusion) decreases from 7.5 {angstrom} to 2.5 {angstrom}, but exceeds the thickness of the individual layers for the smallest periods. HRTEM shows disruption of layer continuity at d = 10 {angstrom} and a loss of visible composition modulation at d = 8 {angstrom}, while the reflectivity begins to fall sharply near d = 15 {angstrom}. This is consistent with incomplete or discontinuous W layers below about d = 15 {angstrom}, and compares reasonably with other experimental and theoretical data on growth of very thin metal films.
- OSTI ID:
- 644301
- Report Number(s):
- CONF-9704224-; ISSN 1359-6454; TRN: 98:008227
- Journal Information:
- Acta Materialia, Vol. 46, Issue 11; Conference: Workshop on coupled property issues in integrated microstructures, Monterey, CA (United States), 4-7 Apr 1997; Other Information: PBD: 1 Jul 1998
- Country of Publication:
- United States
- Language:
- English
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