Parallel Sputter Coating

Sputtering technologies offer an even faster procedure at the cost of the versatility of the catalysts produced. Sputtering produces catalysts with a dense surface layer. These catalysts are different from industrially used catalysts, which usually have a larger surface area. The BET surface area of sputtered catalysts is below 1 m2 g 1 and thus much lower than the surface area of the wash-coated catalysts (usually above 60 m2 g1). However, if catalysts for a fast reaction have to be screened, the gas components will mainly react at the surface of the catalyst and the porosity of the catalyst is not important. 

During this process, the layer thickness of three catalyst components on a titer-plate was simultaneously varied in such a way that 48 single catalyst mixtures were obtained in a one-step process. Thus, the amount of each catalyst component in the mixture could either be decreased or increased, resulting in a homogeneous multi-component layer. 

Every orifice is supplied with an individual geometry. The rotation frequency of the revolving shuttle influenced the homogeneity of the layer. A faster rotational speed will result in thinner sublayers and thus in an increased layer homogeneity. However, the rotational speed is restricted by mechanical properties of the turn table (Table 3.2). 

For the single component zirconium, the gradient of the layer thickness was measured on a silicon monocrystalline wafer. The resulting thickness gradient is 

Pressure (mbar) Cas Power (Wj Targets Rotational speed (rpm) Deposit rate (nm min-1) Substrates 

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According to our experience, coating-related stresses have the most unfavorable effect on the crystal. This effect is particularly pronounced in the presence of gas, e.g. in sputter processes or reactive vacuum coating or sputter processes. If the Z value for solid material is known, it is better to use it than to carry out automatic determination of the auto Z ratio". In cases of parallel coating and coating sequences, however, automatic Z determination is significantly better. 

Lavik and Campbell studied coatings sputtered at temperatures between 150°C and 427°C, and found a high degree of crystallinity. They estimated that about 30 per cent of the crystais were oriented with their basal planes parallel to the substrate surface, and 70 per cent perpendicular to the surface. Most workers now appear to assume that above 70°C an even higher proportion of the crystals have the perpendicular orientation and this is discussed later. 

When PtClg - ion is incorporated into the surface film of poly-Mv2+ and reduced to Pt(0), a uniform distribution of Pt(0) is found throughout the film using Auger spectroscopy of the slowly sputtered surface (32). Interestingly, this depth profile analysis revealed a thin (20A) coat of SiO between the semiconductor surface and polymer layer. The most significant finding, however, was the successful reduction of water mediated by these illuminated electrodes. Bard and Abruna (34) conducted nearly parallel experiments on p-Si, but their poly-Mv2+ films were deposited by evaporation or electroprecipitation of the performed polymer. They also platinized their films and showed photo-assisted electrochemical reduction of water to produce H2. 

Usually, when ferroelectric thin film samples formed as metal-electrode/film/metal-electrode sandwich structures, we can observe a symmetric P-E loop. The ferroelectric P-E hysteresis loop of PZT thin film samples fabricated by the sol-gel method were measiued by using a modified Sawyer-Tower bridge. The PZT films were coated on titanium foil-substrates and were heat-treated at 700°C and 400°C, respectively. The samples were prepared as a sandwich structure of metal electrode (sputtered Au)/PZT film/titanimn-electrode (substrate). The observed P-Eloops ofthese samples are shown in Figure22-8(a) and (b). Similarly, a parallel study was conducted for crystalline and amorphous BaTiOs thin films fabricated by the sol-gel method. A P-E hysteresis loop was observed on the amorphous BaTiOs thin film (Xu and Mackenzie, 1994). 

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