@misc{GrafeLoeserSchmitzetal., author = {Grafe, Hans-Joachim and L{\"o}ser, Wolfgang and Schmitz, Steffen and Sakaliyska, Miroslava and Wurmehl, Sabine and Eisert, Stefan and Reichenbach, Birk and Acker, J{\"o}rg and Rietig, Anja and Ducke, Jana}, title = {NMR investigation of boron impurities in refined metallurgical grade silicon}, series = {Physica status solidi. A, Applications and Materials Science}, volume = {212}, journal = {Physica status solidi. A, Applications and Materials Science}, number = {9}, issn = {1862-6319}, doi = {10.1002/pssa.201431908}, pages = {2031 -- 2036}, abstract = {The nuclear magnetic resonance (NMR) method was applied for tracking boron impurities in the refining process of metallurgical grade (MG) silicon. From the NMR signal of the 11B isotope at an operating temperature 4.2 K, the boron concentration can be estimated down to the order of 110 wppm B. After melting and resolidification of MG-Si alloyed with Ca and Ti, a major fraction of B impurities remains in the Si solid solution as inferred from the characteristic NMR frequency. The alloying element Ti does not form substantial fractions of TiB2. Acid leaching of crushed powders of MG-Si alloyed with Ca and Ti can diminish the initial impurity content of B suggesting its accumulation in the grain boundary phases.}, language = {en} }