Trimethylindium

Trimethylindium (abbr: TMI), In(CH₃)₃, (CAS #: 3385-78-2) is the preferred metalorganic source of Indium for Metalorganic vapour phase epitaxy (MOVPE) of indium-containing compound semiconductors, such as InP, InAs, InN, InSb, GaInAs, InGaN, AlGaInP, AlInP, AlInGaNP etc. TMI is a white, crystalline and sublimable solid, with melting point 88 ºC. 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. > 88º C) and reaches 101 ºC and above. TMI is also reported to exhibit autocatalytic behavior during its thermal decomposition ^[1]. Hence TMI needs to be handled with utmost care and caution, e.g. stored in preferrably cool, dry place at 0-25º C, and operating temperatures not to exceed 50 ºC to avoid deterioration.

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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 [2] [3]}, which were not practically achievable in the past.

References

1. ^ Chemistry of Materials (2000); doi:10.1021/cm990497f
2. ^ Journal of Crystal Growth (2002); doi:10.1016/S0022-0248(02)01854-7
3. ^ Journal of Crystal Growth (2004); doi:10.1016/j.jcrysgro.2004.09.006

• Interactive Vapor Pressure Chart for metalorganics.