CryoSAS - Cryogenic Silicon Analysis System
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CryoSAS Cryogenic Silicon Analysis System The CryoSAS is a high sensitivity system for the quality control of solar and electronic grade silicon material according to international ASTM/SEMI standards. Although sample cooling to very low temperatures is required, the fully automated system is easy to operate, as it does not require cryogenic liquids. Quantification of group III and V shallow impurities (B, P, As, Al, Ga, Sb) in single crystal Si down to the low ppta range [2] Quantification of substitutional carbon in polysilicon or single crystal Si down to the low ppba range [3] Quantification of interstitial oxygen in polysilicon or single crystal Si down to the low ppba range Closed cycle cooling that requires no cryogenic liquids Fully automated measurement cycle and data evaluation, including report generation Innovation with Integrity Early publications on silicon impurity determination showed that Fourier transform infrared (FT-IR) spectroscopy at room or low temperature is an ideal tool for semiconductor research and silicon quality control [1]. Very low detection limits are achievable, in the parts per billion atoms range (ppba, 10 -9 ), which corresponds to a concentration of ca. 5x1013 atoms/cm3. For single crystal material at liquid He temperatures, detection limits as low as parts per trillion atoms (ppta, 10 -12 ) can be achieved for some impurities. The expertise required to operate a research grade spectrometer and cryostat, or to store and handle cryogenic liquids, is frequently not available in a typical analytical laboratory. The Cryogenic Silicon Analysis System (CryoSAS) was therefore developed as a dedicated all-in-one system for the low temperature impurity analysis and quality control of silicon crystals. Optimized for operation in the industrial environment, the CryoSAS combines a high performance Bruker FT-IR interferometer with a built-in, closed cycle cryo-cooling system that does not require any liquid nitrogen or liquid helium. CryoSAS operation is completely automated, and includes reporting of the analysis results according to SEMI and ASTM standards [2,3].

High sensitivity Difference spectrum: Absorbance Units View inside CryoSAS sample compartment with installed sample holder Intuitive quality control software with touch screen operation Operator performing Silicon quality control with CryoSAS Absorbance Units Specialized optical components The optical components of the CryoSAS are optimized for the quantification of group III and V shallow impurities such as boron and phosphorous, as well as substitutional carbon (Cs). These are the most important impurities in solar and electronic grade Silicon, but the CryoSAS can also be used for the...