ISSN 1017-2548(Print)
ISSN 2234-8530(Online)
Volume 36, Number 2
JKCSEZ 36(2)
April 20, 1992 

A procedure for spectrophotometric determination of traces of phosphorus(P) in high-purity trichlorosilane(TCS) is proposed using an adsorptive separation. PCl3, which is a dominant P impurity within TCS, is first oxidized by oxygen to a stable form as POCl3. AlCl3 is selected as an adsorbent which forms a thermally stable complex with POCl3 in TCS and can be well dissolved in aqueous ethanol solution. The proposed adsorptive separation method is free from the formation of silica gel and gas bubbles during the colorimetric analysis of TCS. The method reveals that the P concentration in a semiconductor-grade TCS is 5.32 μg/ℓ within the standard deviation of ± 17%. On the other hand, the P concentration of the purified TCS which is separated from the AlCl3·POCl3 complex is reduced to be less than 0.15 μg/ℓ, showing the efficient applicability of AlCl3 to the wet chemical analysis. The proposed method is also tested to verify the effectiveness of other well-known adsorbents.