Analysis of Elemental Impurities in Photovoltaic Silicon by Inductively Coupled Plasma Mass Spectrometry

Abstract

A new, simple sample preparation method which results in minimal contamination has been developed for the ultratrace interference-free analysis of solar grade silicon wafers by Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). Using Dynamic Reaction Cell (DRC) technology with patented dynamic bandpass tuning (DBT) and robust hot plasma conditions, the determination of many critical elements, including boron and phosphorus, without impact from interfering species is shown. For method validation, the mean results of a PV silicon wafer sample (purity > 6N) prepared with this new methodology and analyzed by ICP-MS were cross-checked with the data obtained from Glow Discharge Mass Spectrometry (GDMS). The comparative data of these two different technologies highlights the advantage of the ELAN DRC II ICP-MS for the fast determination of impurities in the PV silicon, over GDMS - which was found to be not as cost effective or time efficient.