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Reactive sputtering is a very complex and nonlinear process. There are many parameters involved. Normally it is not possible to vary a single parameter independently of the others. It is therefore very difficult to characterize the process based on experimental observations. A better understanding of the reactive sputtering mechanism is needed. We have suggested a simple model for the reactive sputtering process. This model is primarily based on well-known gas kinetics, transferred to this application. With this model it is possible to theoretically predict different processing conditions and actually study the influence of a change in an individual parameter value. The results may then be used to predict optimal experimental conditions. With this technique it is also possible to study means of affecting the well-known hysteresis effect. This article is specially devoted to explain the width of the hysteresis region and how it is affected by the sputtering intensity. Experimental results are presented that support the validity of the proposed model. It was found that the hysteresis width increases in proportion to the rf power fed to the sputtering target. It is thus not possible to eliminate the hysteresis effect by any kind of variation of the sputtering intensity.The effect of the hysteresis effect on the composition limitation of the deposited films will also be described.

Animal studies suggest that administration of vitamin A to rats with experimental urinary tract infection decreases the frequency of renal scars (Kavukçu et al., BJU Int 83(9):1055-1059, 1999). The aim of this study was to determine the effect of vitamin A on the rate of permanent renal damage in children with acute pyelonephritis. Fifty children, median age of 24 months (range 2-144), with first-time pyelonephritis verified by an uptake defect on acute dimercaptosuccinic acid (DMSA) scan were included in the study and randomly allocated to the case or control groups. All were given intravenous ceftriaxone for 10 days followed by oral cephalexin for 3 months. Cases in addition were given a single intramuscular dose of vitamin A, 25,000 U for infants below 1 year of age and 50,000 U for older children. At the repeat DMSA scan after 3 months, five of 25 cases (20%) and 17 of 25 controls (68%) had abnormal findings (p = 0.001). In conclusion, administration of vitamin A was associated with a significantly lower rate of permanent renal damage.

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Novel designs of current-mode Ternary minimum (AND) and maximum (OR) are proposed in this paper based on Carbon NanoTube Field Effect Transistors (CNTFET). First, these Ternary operators are designed separately. Then, they are combined together in order to generate both outputs concurrently in an integrated design. This integration results in the elimination of common parts when both functions are required at the same time. The third proposed current-mode integrated circuit generates both ternary operators with the usage of only 30 transistors. The new designs are composed of three main parts: (1) the part which converts current to voltage; (2) threshold detectors; and (3) the parallel paths through which the output current flows. Unlike the previously presented structure, there is no need for any constant current source within the new designs. This elimination leads to less static power dissipation. The second proposed current-mode segregated Ternary minimum operates 43% faster and consumes 40% less power in comparison with a previously presented structure.

Computer process modeling has become an important tool in the development of new thin-film processes. Previously, we presented a model that successfully describes the complex behavior of the reactive sputtering of a single-element target. The model enables one to predict, e.g., the hysteresis effect and the composition of the deposited film. There exists, however, a demand for developing reliable reactive-sputtering processes for more complicated materials. This calls for an extended reactive-sputtering model including more than one target element. In this article, we will for the first time present an extension of our previous model now taking the effect of multi component targets into consideration. The transition from metallic-to compoundsputtering mode normally occurs at different levels for different single-element targets. The new extended reactive-sputtering model predicts the transition from metallic to compound mode during multicomponent reactive sputtering of thin films. The results indicate that under normal operating conditions, only one transition region exists irrespective of the number of target elements involved in the process. This is experimentally verified for the process of reactive cosputtering of Al + Ti in an Ar/0 2 atmosphere. We wi.ll also point out the complex composition behavior of the reactive-cosputtering process as compared with reactive sputtering from an alloy target.

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