Microelectronic device applications

As a consequence of their superior physical and chemical properties, silicon nitride and silicon carbonitride films have become increasingly important for both structural and microelectronic device applications. Chemical vapor depositions (CAH)) has become a major technique for the synthesis of these thin film materials flO]. 

Artificial-potential-barrier structures appear in a number of important microelectronic device applications. The best known is probably the laser diode. These ubiquitous devices are deceptive in their outward simplicity - a single small chip of material... 

One of the more recent advances in XPS is the development of photoelectron microscopy [ ]. By either focusing the incident x-ray beam, or by using electrostatic lenses to image a small spot on the sample, spatially-resolved XPS has become feasible. The limits to the spatial resolution are currently of the order of 1 pm, but are expected to improve. This teclmique has many teclmological applications. For example, the chemical makeup of micromechanical and microelectronic devices can be monitored on the scale of the device dimensions. 

The growing interest in volatile silyl-metal complexes for chemical vapor deposition reactions should also be mentioned. This technique is extremely useful for the preparation of silicide films in microelectronic devices. Further examples of applications of silicon-metal compounds are given in the appropriate sections. 

It was also observed that, with the exception of polyacetylene, all important conducting polymers can be electrochemically produced by anodic oxidation moreover, in contrast to chemical methoconducting films are formed directly on the electrode. This stimulated research teams in the field of electrochemistry to study the electrosynthesis of these materials. Most recently, new fields of application, ranging from anti-corrosives through modified electrodes to microelectronic devices, have aroused electrochemists interest in this class of compounds... 

In nanotechnology, dimensions of interest are shrinking from the fiva to the nm range. For many microelectronic devices, such as laterally structured surfaces, particles, sensors, their physical as well as their chemical properties are decisively determined by their chemical composition. Its knowledge is mandatory for understanding their behavior, as well as for their successful and reliable technical application. This presents a challenge for TOF-SIMS, because of its demand for the unique combination of spatial resolution and sensitivity. 

In order to discuss the signatures of localization and delocalization and its significance for the application of nanoclusters in microelectronic devices, the following chapters will give examples about the electrical properties of nanoclusters arrays, distinguished according to their dimensionality. 

The silicon substrate constitutes a very interesting support for facilitating the integration in microelectronic devices. The electrochemical and electroanalytical fields can gain remarkable benefits from the silicon-based miniaturization devices, especially if arrays of metal electrodes can be fabricated. An understanding of the electrochemical properties of CNTs directly attached to silicon is thus essential for their potential application in developing silicon-based electrochemical or (bio)electrochemical... 

Finally, for practical reasons it is useful to classify polymeric materials according to where and how they are employed. A common subdivision is that into structural polymers and functional polymers. Structural polymers are characterized by - and are used because of - their good mechanical, thermal, and chemical properties. Hence, they are primarily used as construction materials in addition to or in place of metals, ceramics, or wood in applications like plastics, fibers, films, elastomers, foams, paints, and adhesives. Functional polymers, in contrast, have completely different property profiles, for example, special electrical, optical, or biological properties. They can assume specific chemical or physical functions in devices for microelectronic, biomedical applications, analytics, synthesis, cosmetics, or hygiene. 

Details of building specific types of microelectronic devices are well described by Grovenor15 as an illustration, we consider only the chemical techniques involved in making a metallic contact to a silicon wafer surface. Preparation of a wafer of Si or other material and application of epitaxial layers of semiconducting or insulating materials, if required, were outlined in Section 19.2.1. The construction of shaped features on the wafer is usually done by photolithography, or ion- or electron-beam variants thereof. 

Donor adducts of aluminum and gallium trihydride were the subject of considerable interest in the late 1960s and early 1970s.1 Thin-film deposition and microelectronic device fabrication has been the driving force for the recent resurgence of synthetic and theoretical interest in these adducts of alane and gallane.24 This is directly attributable to their utility as low-temperature, relatively stable precursors for both conventional and laser-assisted CVD,59 and has resulted in the commercial availability of at least one adduct of alane. The absence of direct metal-carbon bonds in adducts of metal hydrides can minimize the formation of deleterious carbonaceous material during applications of CVD techniques, in contrast to some metal alkyl species.10, 11... 

Electronic materials encompass a wide variety of solids and their applications. Nevertheless, the area that has become synonymous with electronic materials is microelectronics. This situation has arisen because of the rapid and pervasive development and growth of microelectronic devices or integrated circuits (ICs). Although there are literally hundreds of individual steps that compose the manufacture of an IC, essentially each one is a chemical process. Thus, this book emphasizes the fundamental chemical engineering principles involved in the fabrication of ICs. This volume is intended to be a tutorial tool rather than a comprehensive review. Additional details on specific topics can be obtained from the extensive list of references at the end of each chapter. 

Since most of the papers in this symposium deal primarily with the role of surface composition in industrial applications, in this section we depart from that path to consider an example of the role of surface structure in the performance microelectronics devices. 

Air-Water Interface. Organized films of surfactants and phospholipids at the air-water interface are of interest in biophysics, general interfacial chemistry, and have relevance to the self-assembling aggregates, which are viewed as having potential applications in non-linear optics and as microelectronic devices (122). FT-IR spectroscopy has recently been applied to the problem of obtaining information about amphiphiles at the air-water interface. 

Microfabrication is increasingly central to modern science and technology. Many opportunities in technology derive from the ability to fabricate new types of microstructures or to reconstitute existing structures in down-sized versions. The most obvious examples are in microelectronics. Microstructures should also provide the opportunity to study basic scientific phenomena that occur at small dimensions one example is quantum confinement observed in nanostructures [1]. Although microfabrication has its basis in microelectronics and most research in microfabrication has been focused on microelectronic devices [2], applications in other areas are rapidly emerging. These include systems for microanalysis [3-6], micro-volume reactors [7,8], combinatorial synthesis [9], micro electromechanical systems (MEMS) [10, 11], and optical components [12-14]. 

Thin semiconductor films (and other nanostructured materials) are widely used in many applications and, especially, in microelectronics. Current technological trends toward ultimate miniaturization of microelectronic devices require films as thin as less than 5 nm, that is, containing only several atomic layers [1]. Experimental deposition methods have been described in detail in recent reviews [2-7]. Common thin-film deposition techniques are subdivided into two main categories physical deposition and chemical deposition. Physical deposition techniques, such as evaporation, molecular beam epitaxy, or sputtering, involve no chemical surface reactions. In chemical deposition techniques, such as chemical vapor deposition (CVD) and its most important version, atomic layer deposition (ALD), chemical precursors are used to obtain chemical substances or their components deposited on the surface. 

Chemically modified electrodes (CMEs) represent a modern approach to electrode systems. These electrodes rely on the placement of a reagent onto the surface, to impart the behavior of that reagent to the modified surface. Such deliberate alteration of electrode surfaces can thus meet the needs of many electroanalytical problems, and may form the basis for new analytical applications and different sensing devices. Such surface functionalization of electrodes with molecular reagents has other applications, including energy conversion, electrochemical synthesis, and microelectronic devices. 

For a number of years, polymers such as polyimide, have been subjected to widespread research, because of their increasing importance as dielectric materials for the fabrication of microelectronic devices (1). In particular, the adhesion of metal or polyimide films deposited on polyimide substrates and vice versa, is of considerable importance in most applications, and many studies ranging from adhesion testing to detailed spectroscopic analysis of interfaces have been reported previously (2,3.. 5.6). 

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