Microelectronics, application fields

Figure 9.3 Application fields for trace and ultratrace analysis in materials science and Microelectronics. (j.S. Becker and FI.J. Dietze, Int. j. Mass Spectrom., Ion Proc. 197, 1-35 (2000). Reproduced by permission of Elsevier.)...

Given the very high level of technological infrastructure that already exists for these elemental semiconductors because of microelectronics applications, it is not surprising that both these materials were examined early on in the evolution of the field of photoelectrolysis of water. As mentioned in an introductory paragraph, cathodic reduction of the Ge surface is accompanied by H2 evolution.58,559 However, we are not aware of studies under irradiation of Ge electrodes from a HER or OER perspective. The extreme instability of this semiconductor in aqueous media coupled with its low band gap (Eg = 0.66 eV) make it rather unattractive for water photosplitting applications. 

The handbook by Pierson contains a very useful discussion of specific materials and CVD processes, as does the book by Morosanu. The books by Hitchman and Jensen, and by Sherman, concentrate more on silicon microelectronics applications, while the books by Stringfellow and by Jones and O Brien concentrate on compound semiconductor applications. The book by Kodas and Hampden-Smith and the series of proceedings volumes, represented by Sandhu et al. ° focus on CVD of metals. A separate series of books on CVD are the proceedings of the International Conferences on CVD held every two to three years since circa 1967, primarily sponsored by the Electrochemical Society. These provide useful snapshots of the field at various times, are a few of the more recent volumes in this series. Books by Vossen and Kern " and Smith,cover CVD as parts of their larger treatments of thin film deposition. 

Lately, the nasal route is receiving attention for the management of postoperative pain. Mucosal administration requires only a 1.1-1.5 times higher dose of fentanyl than the intravenous dose. ° For this new application field, called PCINA (patient-controlled-intranasal-analgesia), the pharmaceutical industry demands safety precautions of the delivery device, which can be fulfilled through implementation of intelligent microelectronic features. 

Since 1950s, there have been three traditional fields of application for molecular sieves and porous materials 1) separation, purification, drying and environment treatment process 2) petroleum refining, petrochemical, coal and fine chemical industries 3) ion-exchange, detergent industry, radioactive waste storage, and treatment of liquid waste. In addition to the traditional application fields, zeolites and related porous materials may also find applications in new areas such as microelectronics and molecular device manufacture. 

The configuration of a CVD system may adopt numerous forms depending on the particular application. For example, continuous fiber-coating systems are inappropriate to the demands of the microelectronics device field, yet each relies on indispensable CVD steps for major commercial success. The overall CVD system can be segmented into three general components reactant input, reaction zone, and the reaction coproduct removal system. 

SiC-precursor processing can be subdivided into gas (chemical vapor deposition, CVD) and condensed phase methods. CVD, because of microelectronic applications, has spawned an entire field. It will be discussed here only very briefly. We will focus more intensively on the use of silicon-containing organometaUic precursors as condensed phase sources of ceramic materials. 

A number of different types of nanoporous materials for use in low dielectric constant iq lications have been developed in recent years, including nanoporous silica, polyimides, poly(arylefhers), and poly(methyl silsesquioxanes). Recently, much research has been done in die field of siqiercritical carbon dioxide (SCCO2) and its use in the synthesis of polymers for microelectronic applications. A variety of different methods using supercritical CO2 to form micro- and nanoporous materials towards applications in the microelectronic industry are described. 

Polpmides have excellent thermal stability, solvent resistance, radiation resistance, wear resistance, hydrolytic stability, low dielectric constant, high mechanical properties, good chemical resistance and a low dielectric constant. Due to these superior properties, the application field of polyimide has generally been enlarged from printed circuit boards and electrical insulation layers in microelectronics to functional layers of humidity sensors, shielding layers for sensor surfaces and novel platforms for thermal sensor devices, temperature sensor arrays, micro-hotplates integrated into gas sensors and biosensors. 

Different fields of application require the knowledge of interfacial phase behavior between gaseous molecules and polymers. New application fields appear with the rapid growth of information technology, for which ongoing downscaling of microelectronics evolves into nanoelectronics. The development of highly ordered... 

The invention of the germanium transistor in 1947 [I, 2] marked the birth of modem microelectronics, a revolution that has profoundly influenced our current way of life. This early device was actually a bipolar transistor, a structure that is mainly used nowadays in amplifiers. However, logical circuits, and particularly microprocessors, preferentially use field-effect transistors (FETs), the concept of which was first proposed by Lilicnficld in 1930 [3], but was not used as a practical application until 1960 [4]. In a FET, the current flowing between two electrodes is controlled by the voltage applied to a third electrode. This operating mode recalls that of the vacuum triode, which was the building block of earlier radio and TV sets, and of the first electronic computers. 

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... 

The foregoing examples give initial impressions of how DNA can be nsed to fnnctionalize solid supports with respect to applications, for instance, in the field of microelectronics. In the following, the use of laterally structured substrates is addressed. In particnlar, the generation and applications of microstrnctnred snpports fnnctionalized with nncleic acid molecules will be discussed. 

Wegeng et al. refer to the low-cost, mass production of microstructures from metals, ceramics, and plastics as a crucial element for widespread application [Ij. Micro technologies, they say, are generally conducive for mass production however, this has so far only been proven for the field of microelectronics. 

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