Metalorganics
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Metalorganics are also known as organometallics or metallo-organics or organo-inorganics, and are used extensively in metalorganic vapour phase epitaxy (MOVPE) of compound semiconductors and Atomic Layer Deposition (ALD) in silicon-based semiconductors.
Metalorganics can be defined as the compounds involving a bonding interaction (covalent or ionic, localized or delocalized) between one or more carbon atoms of an organic moiety and a metal atom or atoms (of main group, lanthanides, actinides, or transition elements). It is worthwhile to note that this definition also encompasses the organic compounds of the metalloids (such as B, Si, Ge, As and Te). Certain metal-containing organic compounds that do not contain metal-carbon bonds are also considered as metalorganics - provided they closely simulate the metalorganic compounds by definition, e.g. the class of metal hydrides, metal alkoxides, metal thiolates, metal amides and metal phosphides.
Ultrapure metalorganics are sources for optoelectronic and microelectronic applications (e.g. MOCVD and ALD), with highest purity of the order of 99.9999% ("six nines") or greater. These ultrapure metalorganic sources are manufactured by using specially developed innovative synthetic routes, and as such are lowest in particles and deleterious impurities (e.g. metallic, organic and oxygenated etc) at the levels below parts per billion (ppb) and frequently reaching a part per trillion (ppt) level.
[edit] Vapor pressures of metalorganics
The vapour pressure of a metalorganic precursor is a crucial parameter that is used to govern the precise concentrations of metalorganic precursors entering the reactor, and subsequently the rate of deposition in MOVPE process. Hence knowing the vapour pressures most accurately is vital to the MOVPE process and the semiconductor growers.[1]
[edit] Environment, Health and Safety Aspects
As MOVPE has become well-established production technology, there are equally growing concerns associated with its bearing on personnel and community safety, environmental impact and maximum quantities of hazardous materials (such as gases and metalorganics) permissible in the device fabrication operations. The safety as well as responsible environmental care have become major factors of paramount importance in the MOVPE-based crystal growth of compound semiconductors.
