Silicon computer chips

Because of the possibility of focusing laser beams, tlrin films can be produced at precisely defined locations. Using a microscope train of lenses to focus a laser beam makes possible tire production of microregions suitable for application in computer chip production. The photolytic process produces islands of product nuclei, which act as preferential nucleation sites for further deposition, and tlrus to some unevenness in tire product film. This is because the subsuate is relatively cool, and therefore tire surface mobility of the deposited atoms is low. In pyrolytic decomposition, the region over which deposition occurs depends on the drermal conductivity of the substrate, being wider the lower the thermal conductivity. For example, the surface area of a deposit of silicon on silicon is nanower dran the deposition of silicon on silica, or on a surface-oxidized silicon sample, using the same beam geomeU y. 

C04-0145. Silicon tetrachloride is used in the electronics industry to make elemental silicon for computer chips. Silicon tetrachloride is prepared from silicon dioxide, carbon graphite, and chlorine gas. 

Silicon s atomic structure makes it an extremely important semiconductor. Highly purified silicon, doped with such elements as boron, phosphorus, and arsenic, is the basic material used in computer chips, transistors, sUicon diodes, and various other electronic circuits and electrical-current switching devices. Silicon of lesser purity is used in metallurgy as a reducing agent and as an alloying element in steel, brass, and bronze. 

How is the silicon employed in optical fibers and computer chip manufacture related ... 

Germanium, Ge (number 32), computer chips operate faster than silicon, Si (number 14), computer chips. So how might a gallium, Ga (number 31), chip compare with a germanium chip ... 

Modern computer chips are made by chemical etching of silicon wafers, using "masks" to produce the tiny circuitry. 

Computer chips are produced from wafers of silicon, a semimetal. 

The silicon used for making solid-state semiconductor devices such as transistors, computer chips, and solar cells must be ultrapure, with impurities at a level of less than 10 7% (1 ppb). For electronic applications, silicon is purified by converting it to SiCl4, a volatile liquid (bp 58°C) that can be separated from impurities by fractional distillation and then converted back to elemental silicon by reduction with hydrogen ... 

Metalloids are sometimes called semiconductors. These elements can conduct electricity, although not as well as metals. They may gain or lose electrons when they react with other elements. The most famous semiconductor element is silicon, which is used to make computer chips. Metalloids are found between metals and nonmetals on the periodic table. 

Metalloids (or semimetals) have properties intermediate between the metals and nonmetals and are listed in blue-gray boxes in Figure 2.7. Metalloids have a shiny luster, but they are less malleable and ductile than metals. They conduct electricity, but not nearly as well as metals. For this reason, semimetals are called semiconductors. Silicon is the most well known of the semimetals because of its use in constructing semiconductor computer chips. 

Silicon (Si) Silicon is a lustrous silvery gray material. Because silicon conducts electricity, but not as well as a metal, silicon is classified as a semimetal. Crystals of pure silicon that have been doped with arsenic or gallium are known as semiconductors and are used to fabricate computer chips. Silicone rubbers are polymers containing silicon, oxygen, and various hydrocarbon groups, and are used in applications ranging from sealants to breast implants. 

Displacement. A displacement reaction (also called a single replacement reaction) occurs when an element reacts with a compound to form a new compound and release a different element. An example is the reaction that releases silicon (Si) from silicon dioxide (sand), Si02, via its reaction with carbon. Carbon monoxide, CO, is the reaction s other product. When further purified, the silicon can be used in computer chips. 

Atomic Force Microscopy (AFM) This module examines the techniques behind AFM and shows its applications in studying surfaces, particularly silicon surfaces, such as those that might be used in semiconductors and computer chips. 

Currently silicon is still one of the most important semiconductors as it is the basis of any computer chip. It exhibits an indirect band gap of 1.1 eV at room temperature in the microcrystalline phase. Similar to Ge, silicon nanoparticles show a size-dependent photoluminescence. It was reported by Katayama el al. that a thin Si layer can be electrodeposited in l-ethyl-3-methylimidazolium hexafluorosilicate at 90 °C [44], However, upon exposure to air the deposit reacted completely to SiC>2, which makes it difficult to decide whether the deposit was semiconducting or not. Recently, we showed for the first time that silicon can be well electrodeposited from SiCU in the air and water stable ionic liquid 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)amide ([BMPJTfiN) [45, 46]. This ionic liquid can be... 

When doped with elements of Group 13 or Group 15, silicon is a semiconductor. This property is important in the manufacture of computer chips and photovoltaic cells. 

Q A mountain climber breathes from a container of compressed oxygen gas, a nonmetal. This Persian brass bowl contains inlays of the transition metals silver and gold. Q Silicon crystals, a metalloid, are grown in an inert atmosphere of argon, a nonmetal. The crystals are used in the manufacture of computer chips. 

Examine the elements in green boxes bordering the stair-step line in Figure 6-7. These elements are called metalloids, or semimetals. Metalloids are elements with physical and chemical properties of both metals and non-metals. Silicon and germanium are two of the most important metalloids, as they are used extensively in computer chips and solar cells. Applications that make use of the properties of nonmetals, transition metals, and metalloids are shown in Figure 6-8. Do the CHEMLAB at the end of this chapter to observe trends among various elements. 

With proper safety procedures, radiation can be very useful in many scientific experiments. Neutron activation analysis is used to detect trace amounts of elements present in a sample. Computer chip manufacturers use this technique to analyze the composition of highly purified silicon wafers. In the process, the sample is bombarded with a beam of neutrons from a radioactive source, causing some of the atoms in the sample to become radioactive. The type of radiation emitted by the sample is used to determine the types and quantities of elements present. Neutron activation analysis is a very sensitive measurement technique capable of detecting quantities of less than 1 X 10 9 g. 

Another example of a reaction that involves a limiting reactant is the manufacture of the pure silicon that is used in computer chips or solar cells (Figure... 

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