Quantitative Measurement of Boron and Phosphorus in Solar Grade Silicon Feedstocks by High Resolution Fast-Flow Glow-Discharge Mass Spectrometry

The calibration factors are examined for determination of boron (B) and phosphorus (P) in solar grade silicon samples in the new generation of high resolution fast-flow glow-discharge mass spectrometers (FF-GDMS). It is shown that using the generalized calibration factors from the Standard RSF table, the relative errors observed in the determination of these analytes is not acceptably small for photovoltaic applications. The certified B and P values in NIST SRM 57a Si metal sample do not have the confidence intervals, which would be adequate for refining these calibration factors to the acceptable levels. Thus, well-characterized single crystalline Si wafers with known boron and phosphorus contents traceable to NIST reference materials (SRM 2133 and SRM 2137) were used for accurate calibrations and for establishing good analytical procedures for measurements of wide variety of Si sample forms. The obtained results for these important analytes using the new FF-GDMS procedure are compared to other characterization techniques commonly used in this industry.