Semiconductor advances

Fumio Akiya, Exec. VP-Semiconductor Advanced Materials Yasuhiko Saitoh, Dir.-lnt l Bus. 

Stickney, J.L. (2002) Electrochemical Atomic Layer Epitaxy. Nanoscale Control in the Electrodeposition of Compound Semiconductors. Advances in Electrochemisty Science and Engineering (eds R.C. Alkire and D.M. Kolb), Wiley-VCH, Weinheim, vol. 7, pp. 1-106. 

Shtein, M., Peumans, R, Benziger, J.B., and Forrest, S.R., Direct mask- and solvent-free printing of molecular organic semiconductors. Advanced Materials, 2004a. 16(18) 1615. 

D. J. Milliron, A. P. Alivisatos, C. Pitois, C. Edder, J. M. J. Fr chet, Electroactive Surfactcuit Designed to Mediate Electron Transfer Between CdSe Nanocrystals cuid Orgcuiic Semiconductors. Advanced Materials 2003, 15, 58-61. 

Kochergin VR, FoeU H (2006) Novel optical elements made from porous Si. Mat Sd Eng R 52 93-140 Korotcenkov G, Cho BK (2010a) Porous semiconductors advanced material for gas sensor apphcations. Crit Rev Sohd State 35(1) 1-37... 

Korotcenkov G, Cho BK (2010) Porous semiconductors advanced material for gas sensor applications. Crit Rev Solid... 

Service, R. F. (2006). American Physical Society meeting. Semiconductor advance may help reclaim energy from Tost heat. Science, 311, 1860. 

The war itself also drove the development of improved and miniaturised electronic components for creating oscillators and amplifiers and, ultimately, semiconductors, which made practical the electronic systems needed in portable eddy current test instruments. The refinement of those systems continues to the present day and advances continue to be triggered by performance improvements of components and systems. In the same way that today s pocket calculator outperforms the large, hot room full of intercormected thermionic valves that I first saw in the 50 s, so it is with eddy current instrumentation. Today s handheld eddy current inspection instrument is a powerful tool which has the capability needed in a crack detector, corrosion detector, metal sorter, conductivity meter, coating thickness meter and so on. 

Undeniably, one of the most important teclmological achievements in the last half of this century is the microelectronics industry, the computer being one of its outstanding products. Essential to current and fiiture advances is the quality of the semiconductor materials used to construct vital electronic components. For example, ultra-clean silicon wafers are needed. Raman spectroscopy contributes to this task as a monitor, in real time, of the composition of the standard SC-1 cleaning solution (a mixture of water, H2O2 and NH OH) [175] that is essential to preparing the ultra-clean wafers. 

Many of the fiindamental physical and chemical processes at surfaces and interfaces occur on extremely fast time scales. For example, atomic and molecular motions take place on time scales as short as 100 fs, while surface electronic states may have lifetimes as short as 10 fs. With the dramatic recent advances in laser tecluiology, however, such time scales have become increasingly accessible. Surface nonlinear optics provides an attractive approach to capture such events directly in the time domain. Some examples of application of the method include probing the dynamics of melting on the time scale of phonon vibrations [82], photoisomerization of molecules [88], molecular dynamics of adsorbates [89, 90], interfacial solvent dynamics [91], transient band-flattening in semiconductors [92] and laser-induced desorption [93]. A review article discussing such time-resolved studies in metals can be found in... 

Wang L S and Wu H 1998 Probing the electronic structure of transition metal clusters from molecular to bulk-like using photoeieotron spectroscopy Cluster Materials, Advances In Metal and Semiconductor Clusters vo 4, ed M A Duncan (Greenwich JAI Press) p 299... 

Dunoan M A (ed) 1993-1998 Advances in Metai and Semiconductor Ciusters voi i-iV (Greenwioh JAi) Sooies G (ed) 1990 The Chemicai Physics of Atomic and Moiecuiar Ciusters (Amsterdam North-Hoiiand)... 

The study of organic semiconductors and conductors is highly iaterdisciplinary, involving the fields of chemistry, soHd-state physics, engineering, and biology. This article provides a treatment of the theoretical aspects of organic semiconductors as well as an overview of recent advances ia the field and the uses of these materials based on their conductive and optical properties. 

Light-emitting diodes are the most commercially important compound semiconductor devices in terms of both doUar and volume sales. The 1991 worldwide compound semiconductor device market totaled 2.8 biUion (39). Light-emitting diodes accounted for ca 1.9 biUion of this market. Visible and ir LEDs represented 37 and 30%, respectively. These markets are expected to grow as LEDs are increasingly employed in advanced appHcations. 

Epitaxial crystal growth methods such as molecular beam epitaxy (MBE) and metalorganic chemical vapor deposition (MOCVD) have advanced to the point that active regions of essentially arbitrary thicknesses can be prepared (see Thin films, film deposition techniques). Most semiconductors used for lasers are cubic crystals where the lattice constant, the dimension of the cube, is equal to two atomic plane distances. When the thickness of this layer is reduced to dimensions on the order of 0.01 )J.m, between 20 and 30 atomic plane distances, quantum mechanics is needed for an accurate description of the confined carrier energies (11). Such layers are called quantum wells and the lasers containing such layers in their active regions are known as quantum well lasers (12). 

The main advantages that compound semiconductor electronic devices hold over their siUcon counterparts He in the properties of electron transport, excellent heterojunction capabiUties, and semi-insulating substrates, which can help minimise parasitic capacitances that can negatively impact device performance. The abiUty to integrate materials with different band gaps and electronic properties by epitaxy has made it possible to develop advanced devices in compound semiconductors. The hole transport in compound semiconductors is poorer and more similar to siUcon. Eor this reason the majority of products and research has been in n-ty e or electron-based devices. 

The relevance of photonics technology is best measured by its omnipresence. Semiconductor lasers, for example, are found in compact disk players, CD-ROM drives, and bar code scaimers, as well as in data communication systems such as telephone systems. Compound semiconductor-based LEDs utilized in multicolor displays, automobile indicators, and most recendy in traffic lights represent an even bigger market, with approximately 1 biUion in aimual sales. The trend to faster and smaller systems with lower power requirements and lower loss has led toward the development of optical communication and computing systems and thus rapid technological advancement in photonics systems is expected for the future. In this section, compound semiconductor photonics technology is reviewed with a focus on three primary photonic devices LEDs, laser diodes, and detectors. Overviews of other important compound semiconductor-based photonic devices can be found in References 75—78. 

J. J. Iaou, Advanced Semiconductor Device Physics andModeling, Artech House, Boston, Mass., 1994. 

Reactive Hquid infiltration (45,68,90,93,94) is similar to the CVI process used to make RBSN. Driven by capillarity, a reactive Hquid infiltrates a porous preform and reacts on free surfaces. Reactive Hquid infiltration is used to make reaction bonded siHcon carbide (RBSC), which is used in advanced heat engines and as diffusion furnace components for semiconductor wafer processing. 

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