Title :
Certifying the Degree of Perfection of Silicon Single Crystals for the Avogadro Project by Measuring the Amount of Copper Silicide Precipitated in the Voids
Author :
Spaepen, F. ; Wen, C.Y. ; Quétel, C. ; Aninkevicius, V. ; Filee, K. ; Proost, J. ; Taylor, P.D.P. ; De Bievre, P.
Author_Institution :
Div. of Eng. & Appl. Sci., Harvard Univ., Cambridge, MA
Abstract :
A procedure has been developed for determining the number of missing atoms in a silicon crystal. Possible voids are filled with Cu 5Si by indiffusion of copper. After removal of the interstitially dissolved copper, the samples are digested and the copper content is determined by isotope-dilution mass spectrometry. The detection limit of this highly specific and accurate measurement method was developed sufficiently to certify the degree perfection of the silicon single crystals used to enable a redetermination of the Avogadro constant, NA, to the required level: lower than 2 times 10 -8 NA combined standard uncertainty
Keywords :
constants; copper; copper compounds; mass spectroscopy; silicon; voids (solid); Avogadro constant; Avogadro project; Cu5Si; Si; copper indiffusion; copper silicide; isotope-dilution mass spectrometry; silicon single crystals; Atomic measurements; Copper; Crystalline materials; Crystallization; Crystals; Lattices; Mass spectroscopy; Silicides; Silicon; Uncertainty;
Conference_Titel :
Precision Electromagnetic Measurements Digest, 2004 Conference on
Conference_Location :
London
Print_ISBN :
0-7803-8494-6
Electronic_ISBN :
0-7803-8494-6
DOI :
10.1109/CPEM.2004.305503
