Title :
The influence of Young´s modulus on roundness in silicon sphere fabrication [Avogadro constant]
Author :
Collins, John G. ; Giardini, Walter J. ; Leistner, Achim J. ; Kenny, Michael J.
Author_Institution :
Nat. Meas. Lab., CSIRO, Lindfield, NSW, Australia
fDate :
4/1/1997 12:00:00 AM
Abstract :
Silicon single-crystal spheres for use in accurate determination of the Avogadro constant are fabricated by optical grinding and polishing. Surface profiling of the deviation from sphericity of the spheres shows a strong cubic symmetry on the scale of (20 to 40) mm, which is well correlated with the orientation of the silicon crystal axes and sets a limit on the ultimate shape that can be obtained. This deviation from sphericity can be explained in terms of the variation of Young´s modulus with crystal orientation
Keywords :
Young´s modulus; constants; crystal orientation; elemental semiconductors; optical fabrication; polishing; shape measurement; silicon; Avogadro constant; Si; Si crystal axes orientation; Si sphere fabrication; Young´s modulus; crystal orientation; cubic symmetry; deviation from sphericity; optical grinding; polishing; roundness; surface profiling; ultimate shape; Abrasives; Aluminum oxide; Atomic measurements; Helium; Joining processes; Optical device fabrication; Platinum; Prototypes; Shape; Silicon;
Journal_Title :
Instrumentation and Measurement, IEEE Transactions on
