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[15p-D511-9] Quality of silicon substrate and point defects (9) Non-uniformity of lattice parameter and carbon concentration in Avogadro crystal
Keywords:silicon crystal, lattice parameter, carbon
New International system of units relies on the ultra-precise measurement of lattice parameter (LP), volume and weight of 28Si crystal. Nonuniformity of LP in specimen due to defects degrades the reliability. The measured LP nonuniformity was analyzed here. In the sample with C concentration ([C]) of 1015/cm3 at the bottom of the crystal, 1 dimensional map shows nearly constant LP with repeated sharp dips. Local [C] was estimated to be about 0.1 and 5 x [C]av. Nearly constant LP is equal to LP0 of C-free crystal within the experimental error. Comparison with LP of the Avogadro sample gives its absolute value. It will be fruitful to improve the detection limit of SIMS profiling and analyze the result through segregation kinetics. The effect of point defects and grown-in defects on LP will be examined in the near future.