In this paper cord! level XPS spectra of polycrystalline Fe metal and several oxides are corrected by deconvolution using the ratio maethod for energy loss effects and spectral broadening due to both an achromatic x-ray source and finite analyzer resolution. These ideas are applied to the XPS spectra of Fe, FeO, Fe203, and Fe,O, in order to obtain the intrinsic lineshape. The backscattered electron energy loss spectra are effective in distinguishing Fe and its oxides. For Fe metal and its oxides, the electron energy loss deconvolved spectra have a flat baseline and enhanced resolution. This background removal method is found to be more reliable than either linear or sigmoidal background approximations. This allows for a determination of the relative sensitivity factor for the Fe 2p and 0 1s core levels.

A procedure for covalent binding of DNA to a functionalized mica substrate is described. The approach is based on photochemical cross-linking of DNA to immobilized psoralen derivatives. A tetrafluorphenyl (TFP) ester of trimethyl psoralen (trioxalen) was synthesized, and the procedure to immobilize it onto a functionalized aminopropyl mica surface (AP-mica) was developed. DNA molecules were cross-linked to trioxalen moieties by UV irradiation of complexes. The steps of the sample preparation procedure were analyzed with x-ray photoelectron spectroscopy (XPS). Results from XPS show that an AP-mica surface can be formed by vapor phase deposition of silane and that this surface can be derivatized with trioxalen. The derivatized surface is capable of binding of DNA molecules such that, after UV cross-linking, they withstand a thorough rinsing with SDS. Observations with atomic force microscopy showed that derivatized surfaces remain smooth, so DNA molecules are easily visualized. Linear and circular DNA molecules were photochemically immobilized on the surface. The molecules are distributed over the surface uniformly, indicating rather even modification of AP-mica with trioxalen. Generally, the shapes of supercoiled molecules electrostatically immobilized on AP-mica and those photocross-linked on trioxalen-functionalized surfaces remain quite similar. This suggests that UV cross-linking does not induce formation of a noticeable number of single-stranded breaks in DNA molecules.

This work examines the mechanical performance of thin film coatings from Photosensitive-benzocyclobutene (Photo-BCB) formulations (Cyclotene2 4024, 4026 and 7200), on various substrate surfaces such as Al, Cu, Si, and SiN. The adhesion promoter used was designated AP-3000 and was based on vinyltriacetoxysilane (VTAS), which had been properly hydrolyzed and advanced. Measurement of the interfacial adhesion was performed primarily using the modified Edge Liftoff Test m-ELT. It was found that, by applying the newly developed adhesion promoter, AP-3000, the interfacial energy of Photo-BCB to Al, Cu, Si, and SiN was significantly improved, often approaching the toughness of Photo-BCB, ca. 45 J/m2. The x-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) analyses of the delaminated surfaces of the Photo-BCB/Al structure revealed distinct differences in surface roughness and the chemical composition depending on whether or not adhesion promoter was used. Other parameters important for long term stability (e.g., moisture uptake and thermal stability) of Photo-BCB were also measured. The equilibrium moisture content at 84 percent RH in ambient temperature was low, 0.14 wt percent and the thermally induced weight loss at 330°C in helium atmosphere was less than 1 percent/h. The low moisture absorption and good thermal stability, together with the given mechanical toughness and adhesion, allow the Photo-BCB to be widely usable for various microelectronic packaging applications, for up to 40 μm thick build in the case of silicon substrate. [S1043-7398(00)00701-5]

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Publication costs assisted by the Petroleum Research Fund Erythrosin (2,4,5,7-tetraiodofluorescein) has been attached to Sn02 electrode surfaces either through electrochemical adsorption or covalent attachment. Sn02 electrodes modified with mercaptopropyltrimethoxysilane, 3-(2-aminoethyl)propyltriethoxysilane, or y-aminopropyltrimethoxysilane showed a considerable enhancement of the currents passed during oxidation of erythrosin and a deposition of several monolayers of active chromophore. Erythrosin was covalently attached to the silane-modified Sn02 surfaces by means of an amide bond or by the formation of a thiol bond. Small surface concentrations of the adsorbed and covalently attached dye were easily detected by monitoring the I(3d3/2,5/2) x-ray photoelectron transitions. Sensitization of the Sn02 current/voltage response to visible wavelength light was observed for both the adsorbed and covalently attached dye electrodes. Enhanced stability and efficiency of the photocurrent response was observed for the covalently attached vs. adsorbed dye molecules.