| 1. |
- Bennett, J. M., et al.
(författare)
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Test of Opticlean strip coating material for removing surface contamination
- 2000
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Ingår i: Applied Optics. - 0003-6935 .- 1539-4522. ; 39:16, s. 2737-2739
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Tidskriftsartikel (refereegranskat)abstract
- The strip coating material, Opticlean, which has been reformulated, has been shown to remove 1-5-mu m-diameter particles as well as contamination remaining from previous drag wipe cleaning on a used silicon wafer. In addition, no residue that produced scattering was found on a fresh silicon wafer when Opticlean was applied and then stripped off. The total integrated scattering technique used for the measurements could measure scattering levels of He-Ne laser light as low as a few ppm (parts in 106), corresponding to a surface roughness of <1 Angstrom rms.
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| 2. |
- Lastras-Martínez, L. F., et al.
(författare)
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Optical anisotropy of (001)-GaAs surface quantum wells
- 2001
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Ingår i: Physical Review B Condensed Matter. - 0163-1829 .- 1095-3795. ; 64:24, s. 2453031-2453038
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Tidskriftsartikel (refereegranskat)abstract
- We report a reflectance difference spectroscopy (RDS) study of the optical anisotropy of GaAs:(001) surface quantum wells consisting of a thin GaAs layer (3-30 nm thick) embedded between an arsenic reconstructed surface and an AlAs barrier. The RDS spectra display anisotropic contributions from the free surface and from the GaAs/AlAs interface. By comparing RDS spectra for the c(4×4) and (2×4) surface reconstructions, we separate these two contributions, and demonstrate that the anisotropy around the E1 and E1+Δ1 transitions comprises a component originating from modifications of bulk states near the surface. The latter is attributed to anisotropic strains induced by the surface reconstruction. The experimental data are well described by a model for the RDS response of the multilayer structures, which also takes into account the blue energy shifts and the changes in oscillator strength of the E1 and E1+Δ1 transitions induced by quantum-well confinement.
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| 3. |
- Lindstrom, T, et al.
(författare)
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Total integrated scattering from transparent substrates in the infrared region: validity of scalar theory
- 2000
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Ingår i: Optical Engineering. - : SPIE-Intl Soc Optical Eng. - 0091-3286 .- 1560-2303. ; 39:2, s. 478-487
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Tidskriftsartikel (refereegranskat)abstract
- Integrated light scattering, from thin, transparent silicon wafers with different front and backside surface roughness is investigated. The measurements are made at near normal incidence in the IR wavelength region 5 to 20 μm using an integrating sphere. A method to separate the scattering contribution from each interface for measurements on transparent samples is introduced. Scalar scattering theory is used to calculate the effective root mean square roughness from reflectance and transmittance measurements, and these values are compared to profilometer data, correcting for the different bandwidth limits. Scattering measurements are performed with both the rough and the smooth surface of the wafer oriented toward the light source, which results in additional knowledge. The maximum ratio between the root mean square roughness and the wavelength of the light, to be used in scalar theory, is found to be considerably higher for the transmittance case than for the reflectance case. In agreement with theory, the calculated root mean square roughness is found to be proportional to the refractive index of incident medium in reflectance, and to the difference in refractive indices of incident and refracting medium for the transmittance case.
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| 4. |
- Niklasson, Gunnar A., et al.
(författare)
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Surface roughness of pyrolytic tin dioxide films evaluated by different methods
- 2000
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Ingår i: Thin Solid Films. - 0040-6090 .- 1879-2731. ; 359:2, s. 203-209
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Tidskriftsartikel (refereegranskat)abstract
- The scaling of surface roughness in thin spray pyrolyzed fluorinated tin dioxide films of different thicknesses was obtained from atomic force microscopy. The data show that, within experimental uncertainties, the effective dimensionality of the surface is 2; hence no evidence of fractal surface roughness was found. Other methods – based upon light scattering and cyclic voltammetry – gave additional information on the surface topography. Cyclic voltammetry measurements show that the reaction sites on the surface are distributed in a fractal structure and may be identified with hillocks seen in surface reliefs.
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| 5. |
- Rönnow, Daniel, et al.
(författare)
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Yttrium hydride layer with switchable microwave properties
- 2004
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Ingår i: Thin Solid Films. - : Elsevier BV. - 0040-6090 .- 1879-2731. ; 467:1-2, s. 186-189
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Tidskriftsartikel (refereegranskat)abstract
- We report on switching properties in the microwave region of yttrium hydride. A microstrip line of gold on a quartz substrate was used. A gap in the gold had an yttrium hydride layer of 1.0 ÎŒm thickness with a cap layer of 5 nm palladium and 2 nm aluminium oxide. The yttrium hydride was switched between a metallic and a semiconducting state with the exchange of hydrogen. The transmission (S21) and reflection (S11) coefficients were measured in the range 10 MHz-20 GHz. In the metallic state, the sample works like a microwave transmission line and in its semiconducting state, like a microwave resistor. The transmission coefficient was also measured at 5.0 GHz during hydrogenation and de-hydrogenation.
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