Film models classification

This section describes a methodical procedure that allows reliability issues to be approached efficiently. MEMS reveal specific reliability aspects, which differ considerably from the reliability issues of integrated circuits and macroscopic devices. A classification of typical MEMS-failure modes is given, as well as an overview of lifetime distribution models. The extraction of reliability parameters is a Tack of failures situation using accelerated aging and suitable models. In a case study, the implementation of the methodology is illustrated with a real-fife example of dynamic mechanical stress on a thin membrane in a hot-film mass-airflow sensor. 

So, the systematic bibliography presented in this review, had led us to present the results not by way of formulae, curves and tables which most of the time would have been valid for a special sample only, but by the much better possible comparison of well defined properties. This choice has been determined by the complexity of the results. The treatment of one magnetic property can lead to the report of many curves, the presentation of many large tables, or finally to the exposition of many different models (formulae, hypotheses,...) such that a clear classification will be difficult, if not impossible. Such a situation comes from the fact that numerous papers do not give precisely all the many experimental parameters chemical analysis of the starting bulk material, residual gas analysis in the vacuum, cleanness of the substrates, thickness and composition of the films, presence of a possible sublayer at the film-substrate or at the film-air interfaces. X-ray and electron diffraction patterns, Likewise the exact pos-... 

Blectrodes are therefore an unavoidable component of DBAs and must be explicitly considered from the design stage and included in modeling if one wishes to obtain accurate performanee models. In a recent review, Rosset and Shea (2013) have eategorized electrodes for DBAs as (a) carbonaceous, (b) metallic thin film, or (c) novel. For details, we refer the reader to fliat review and the references provided therein. We follow this classification here, wifli an overview given in Fig. 14. When comparing electrodes, in addition to intrinsic electrical and mechanical properties, one must also consider tiie ease by which the electrodes can be applied and patterned, as well as their lifetime. Different applications require different electrodes. 

De Oliviera and Griffits [235] have studied multilayer adsorption on a homogeneous surface. They have obtained stepwise adsorption, which proved that the sruface films grow in a layer-by-layer mode in the series of the successive first-order phase transitions. A general classification of possible scenarios for the film growth has been presented by Pandit et al. [236] in the framework of a mean field theory for the lattice gas model. 

From this point theories differ as to the precise mechanism of the reaction. Smith and Ewart use three different classifications, depending upon the characteristics of the particular system. However, for the purpose of preparing industrial latices, the following is probably as good a model as any to use, assuming the required stability, conversion and film performance are obtained. 

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