DETERMINATION OF TRACE IMPURITIES IN ORGANOMETALLIC SEMICONDUCTOR-GRADE REAGENTS AND PROCESS CHEMICALS WITH ELECTROTHERMAL VAPORIZATION INDUCTIVELY-COUPLED PLASMA-ATOMIC EMISSION-SPECTROMETRY

Both volatile and non-volatile impurities in semiconductor-grade organometallic reagents are determined by electrothermal vaporization-inductively coupled plasma atomic emission spectrometry (ETV-ICP-AES). Solid or liquid materials are dispensed directly onto a graphite microboat, and application of an appropriate time-temperature programme separates impurities based on their volatility. Calibration methods for volatile impurities (e.g., Si, Sn, Zn in trimethylaluminium) including external calibration, exponential dilution, and direct vapour sampling provide semi-quantitative results. Determination of non-volatile impurities by ETV-ICP-AES can be reasonably performed with aqueous external standard calibration.