SEMI PV25 - Test Method for Simultaneously Measuring Oxygen, Carbon, Boron And Phosphorus in Solar Silicon Wafers and Feedstock by Secondary Ion Mass Spectrometry
This Standard was technically approved by the Photovoltaic – Materials Global Technical Committee. This edition was approved for publication by the global Audits and Reviews Subcommittee on December 8, 2016. Available at www.semiviews.org and www.semi.org in March 2017; originally published October 2011.
Secondary ion mass spectrometry (SIMS) can measure the total bulk concentrations of oxygen, carbon, boron and phosphorus in polished solar silicon wafers and silicon feedstock. Bulk carbon is important because it can form carbon-related defects, such as SiC inclusions. Bulk oxygen is important in boron-doped silicon because a BOx defect can degrade cell efficiency. Boron and phosphorus are common dopants in solar Si wafers, and are difficult to measure directly in solar Si wafers, especially in highly compensated silicon.
The purpose of this Test Method is for the measurement of all four elemental concentrations accomplished in one test and using one SIMS instrument.
This Test Method covers the simultaneous determination of total oxygen, carbon, boron and phosphorus concentrations in the bulk of silicon samples that are prepared from solar silicon wafers or solar silicon feedstock using SIMS.
This Test Method can be used at three stages of solar Si wafers and silicon feedstock: research and development; process check; and verification at the commercial sales/purchase interface.
This Test Method can be used for silicon in which the dopant concentrations by this method are determined to be less than 0.2% (1 × 1020 atoms/cm3) for oxygen, carbon, boron, and phosphorus and > 5 × 1016 atoms/cm3; > 1 × 1016 atoms/cm3; > 1 × 1014 atoms/cm3; and > 2 × 1014 atoms/cm3 , respectively.
This Test Method can be used for silicon irrespective of the amount of compensation in the silicon within the limits of elements specified in ¶ 2.3.
This Test Method can be used for either multi-crystalline or single crystal silicon wafers.
This Test Method is for bulk analysis where the oxygen, carbon, boron and phosphorus concentrations are constant with depth.
Referenced SEMI Standards
SEMI MF2139 — Test Method for Measuring Nitrogen Concentration in Silicon Substrates by Secondary Ion Mass Spectrometry