The recursion method is applied analytically to the Anderson model in the strong disorder limit. The chain basis and chain parameters are determined exactly to lowest order in the hopping energy. It is shown that for all dimensionalities there is a dense spectrum of exponentially localised states with a characteristic length independent of energy and proportional to the ratio of hopping to disorder. This calculation extends the application of the recursion method to all degrees of disorder and answers some questions about denseness of the spectrum, correlation of parameters, and completeness of the chain basis.

MOTS C L~S :X-ray microscopy Microscopie X Electron beam lithography Lithographie 6lectronique SUMMARY : We repon the manufacture of germanium phase zone plates as objective lenses for high resolution X-ray imaging at 2.4nm wavelength. The phase shifting properties of the germanium can be used to enhancc the diffraction efficiency of a zone plate. Zone plate pattems with smcture widths down to 30 nm are generated by low distortion electron beam lithography. The S~C~U T~S are transferred into a 280nm thick layer of germanium by reactive ion etching (RIE) using a highly selective vilevel mask. 100 nm thick baron doped silicon windows made fmm si& crys!n_! ~yafprs serve as high transmission support membranes. Measurements at the BESSY storage ring proved diffraction efficiencies up to 6.2 %. X-ray imaging of a test object showed clearly resolved 30 nm features.

Aluminum (Al) bumps are observed over contact holes when the chemical vapor deposition-physical vapor deposition (CVD-PVD) Al filling process is employed in sub micron technology. Boundaries of bumpy Al grains are formed inside the contact holes, while those of smooth Al grains are formed at the neck of the contact holes. Transmission electron microscopy (TEM) is employed to observe the crystallographic orientation of bumpy and smooth Al grains, and the results are 220 and 111 on {100} silicon surface, respectively. It is known that the growth rate of Al in the 220 direction is higher than that in the 111 direction because of its lower plane density. The difference in growth rate between the 220 direction and the 111 direction is believed to lead to bump formation. A modified PVD Al process to form grain boundaries at the neck of the holes is developed to prevent bumpy Al formation and fill the holes completely.

PACS. 62.20.Qp -Tribology and hardness. PACS. 68.35.Ct -Interface structure and roughness. PACS. 91.60.Ba -Elasticity, fracture, and flow.Abstract. -We model numerically the partial normal contact of two elastic rough surfaces with highly correlated asperities. Facing surfaces are unmated and described as self-affine with a Hurst exponent H. The numerical algorithm is based on Fourier acceleration and allows for numerous and large system computations. We find that for H = 0.6 and H = 0.8, the force F scales as A 1.1 , where A is the contact area. This is in contrast to the law F ∼ A (1+H)/2 , predicting an exponent of 0.8 and 0.9, respectively, which was suggested by Roux et al. (Europhys. Lett., 23 (1993) 277). We propose an explanation for this discrepancy.

No abstract