Deviation of Silicon Lattice Constant due to Isotope Abundance

Main applications of isotopic Silicon in new areas were briefly introduced. The work done by the author’s institute on Silicon isotope separation and measurement of ²⁸Si epitaxial wafer and diodes in early year was presented. For precisely measurement of Avogadro constant as basic metrology unit of kilogram using ²⁸Si, relation of isotope abundance and lattice constant deviation was reduced. Examples were calculated using the relation, thus the requirement of Silicon abundance was estimated.