Trimethylindium
Encyclopedia
Trimethylindium In(CH3)3, (CAS #: 3385-78-2) is the preferred metalorganic source of Indium
for metalorganic vapour phase epitaxy
(MOVPE) of indium-containing compound semiconductor
s, such as InP, InAs, InN
, InSb, GaInAs
, InGaN
, AlGaInP
, AlInP, AlInGaNP etc. TMI is a white, crystalline and sublimable solid, with melting point 88 °C. TMI is known to be pyrophoric, i.e. it ignites sponteneously upon contact with air; and its decomposition is often found to be uncontrollable as the temperature of its surrounding exceeds its melting point (i.e. > 88°C) and reaches 101 °C and above. TMI is also reported to exhibit autocatalytic behavior during its thermal
decomposition
. Hence TMI needs to be handled with utmost care and caution, e.g. stored in preferably cool, dry place at 0-25°C, and operating temperatures not to exceed 50 °C to avoid deterioration. TMI is also known to react extremely violently with oxidizers and polyhalogenated compounds (such as CCl4 or CBrCl3) with which TMI is known to be incompatible. Hence the situations involving admixtures of TMI with oxidizers and polyhalogenated compounds must be avoided as potentially dangerous and explosive.
equations reported in the literature for TMI have been found to offer overestimated vapor pressure of TMI, often by as much as 20–40%. Not knowing the accurate vapor pressure has thus been a concern to crystal growers. In a recent study , it was expermentally confirmed that the vapor pressure equation, P (Torr)=10.98–3204/T (K), provides the most accurate vapor pressures of TMI within a wide range of MOVPE growth conditions.
Indium
Indium is a chemical element with the symbol In and atomic number 49. This rare, very soft, malleable and easily fusible post-transition metal is chemically similar to gallium and thallium, and shows the intermediate properties between these two...
for metalorganic vapour phase epitaxy
Metalorganic vapour phase epitaxy
Metalorganic vapour phase epitaxy , also known as organometallic vapour phase epitaxy or metalorganic chemical vapour deposition , is a chemical vapour deposition method of epitaxial growth of materials, especially compound semiconductors, from the surface reaction of organic compounds or...
(MOVPE) of indium-containing compound semiconductor
Compound semiconductor
A compound semiconductor is a semiconductor compound composed of elements from two or more different groups of the periodic table . These semiconductors typically form in groups 13-16 ,...
s, such as InP, InAs, InN
INN
InterNetNews is a Usenet news server package, originally released by Rich Salz in 1991, and presented at the Summer 1992 USENIX conference in San Antonio, Texas...
, InSb, GaInAs
Gainas
Gainas was an ambitious Gothic leader who served the Eastern Roman Empire as Magister Militum during the reigns of Theodosius I and Arcadius....
, InGaN
Ingan
Ingan is a village in the Punjab province of Pakistan....
, AlGaInP
Aluminium gallium indium phosphide
Aluminium gallium indium phosphide is a semiconductor material.AlGaInP is used in manufacture of light-emitting diodes of high-brightness red, orange, green, and yellow color, to form the heterostructure emitting light...
, AlInP, AlInGaNP etc. TMI is a white, crystalline and sublimable solid, with melting point 88 °C. TMI is known to be pyrophoric, i.e. it ignites sponteneously upon contact with air; and its decomposition is often found to be uncontrollable as the temperature of its surrounding exceeds its melting point (i.e. > 88°C) and reaches 101 °C and above. TMI is also reported to exhibit autocatalytic behavior during its thermal
Thermal
A thermal column is a column of rising air in the lower altitudes of the Earth's atmosphere. Thermals are created by the uneven heating of the Earth's surface from solar radiation, and are an example of convection. The sun warms the ground, which in turn warms the air directly above it...
decomposition
Decomposition
Decomposition is the process by which organic material is broken down into simpler forms of matter. The process is essential for recycling the finite matter that occupies physical space in the biome. Bodies of living organisms begin to decompose shortly after death...
. Hence TMI needs to be handled with utmost care and caution, e.g. stored in preferably cool, dry place at 0-25°C, and operating temperatures not to exceed 50 °C to avoid deterioration. TMI is also known to react extremely violently with oxidizers and polyhalogenated compounds (such as CCl4 or CBrCl3) with which TMI is known to be incompatible. Hence the situations involving admixtures of TMI with oxidizers and polyhalogenated compounds must be avoided as potentially dangerous and explosive.
Semiconductor grade TMI
The advancements in synthesis and purification chemistries have now made it possible to attain highest purity in TMI (99.9999% pure or greater), which is imperative for improved performance of semiconductor applications. Recent reports indicate some of the best electrical properties for InP alloys so far, by MOVPE using highest purity TMI available today, e.g. electron mobilities (Hall data) as high as 287,000 cm²/Vs at 77 K and 5400 cm²/Vs at 300 K, and background carrier concentration as low as 6×1013 cm−3 , which were not practically achievable in the past.Accurate vapor pressure equation for TMI
The vapor pressureVapor pressure
Vapor pressure or equilibrium vapor pressure is the pressure of a vapor in thermodynamic equilibrium with its condensed phases in a closed system. All liquids have a tendency to evaporate, and some solids can sublimate into a gaseous form...
equations reported in the literature for TMI have been found to offer overestimated vapor pressure of TMI, often by as much as 20–40%. Not knowing the accurate vapor pressure has thus been a concern to crystal growers. In a recent study , it was expermentally confirmed that the vapor pressure equation, P (Torr)=10.98–3204/T (K), provides the most accurate vapor pressures of TMI within a wide range of MOVPE growth conditions.
External links
- Interesting research notes by Linus PaulingLinus PaulingLinus Carl Pauling was an American chemist, biochemist, peace activist, author, and educator. He was one of the most influential chemists in history and ranks among the most important scientists of the 20th century...
in re: Trimethylindium and its structure; Notebook # 19, Page 049, August 1955. - Interactive Vapor Pressure Chart for metalorganics.