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We studied the bonding between two flat Si substrates with thin metal films. The bonding was accomplished during thin film sputter deposition on contamination free surfaces of metal films. In this work we used Ti and Pt. Successful bonding of these metal films ͑each having a thickness of 10-20 nm͒ occurred at room temperature over the entire bonded area (12 mmϫ12 mm). Self-diffusion, particularly at grain boundaries and film surface, was the mechanism for bonding. Suitable metal bonding only occurred if the film surface roughness is sufficiently smaller than the self-diffusion length of metals. Particularly in the bonding of Ti to Ti films, transmission electron microscope observation revealed that complete crystalline grains had been formed across the former interface between the single thin Ti films. The interfaceless bonding can be explained by recrystallization of the Ti lattice due to the high self-diffusion coefficient of Ti. This technique would be applied to bonding of wafers to fabricate thin film devices or microsystems. Moreover, this bonding technology can be used with many different thin film materials and various semiconductor substrates.

Membranes consisting of uniform and vertically organized mesopores are promising systems for molecular filtration because of the possibility to combine high-flux and high-rejection properties. In this work, a new generation of mesoporous silica membranes (MSMs) have been developed, in which an organized mesoporous layer is directly formed on top of a porous ceramic support via a Stöber-solution pore-growth approach. Relevant characterization methods have been used to demonstrate the growth of the membrane separation layer and the effect of reaction time and the concentration of the reactants on the microstructure of the membrane. Compared to previous studies using the evaporation-induced self-assembly method to prepare MSMs, an important increase in water permeability was observed (from 1.0 to at least 3.8 L m–2 h–1 bar–1), indicating an improved pore alignment. The water permeability, cyclohexane permporometry tests, and molecular cut-off measurements (MWCO ≈ 2300 Da) were consistent with membranes composed of 2–3 nm accessible pores.

Auger electron spectroscopy, low-energy electron diffraction, and differential reflectometry in the photon energy range 1.5-4.5 eV have been used to study the room-temperature adsorption of O 2 on the SiC 110) surface with an initial 5 X 1 superstructure. The reaction kinetics are complicated. Five adsorption stages can be discerned, the first stage (0-2 L) being remarkably fast with an initial sticking probability near unity. Our results suggest that the surface sites which constitute the higher-order reconstructions and possibly also defects, are highly reactive. In the second stage (2-200 L) the O 2 adsorption can be described by a dissociative process on the firstlayer Si atoms, the sticking probability being about 2 X 10 -3. Incorporation of oxygen into the subsurface Si lattice and possibly also adsorption of a molecular oxygen species are the main processes of the third stage (200-1 ()()() L). In the fourth stage (10 3 -4 X 10 4 L) O 2 adsorption completely removes the dangling bonds. This occurs at 0.79 ± 0.15 monolayer oxygen coverage.The number of dangling bonds per 5 X 1 unit cell (ten atoms) is thus eight or less. The fifth stage ( > 4 X 10 4 L) comprises a slow further oxygen adsorption with a sticking probability of _10-6 : oxygen mainly goes into a bridging position between two first-layer Si atoms in the uppermost chains of the ideal (110) surface. The optical spectrum indicates that the clean Si ( 110) surface probably has several types of (dangling bond) surface states.