Absolute value determination of vacancy concentration in silicon crystals using low-temperature ultrasonic measurements


Absolute value determination of vacancy concentration in silicon crystals using low-temperature ultrasonic measurements

Yamada-Kaneta, H.; Okabe, K.; Akatsu, M.; Baba, S.; Mitsumoto, K.; Nemoto, Y.; Goto, T.; Saito, H.; Kashima, K.; Saito, Y.

For the samples taken from the void region of the CZ silicon crystal grown with the same solidification condition and different thermal histories after the solidification, we measure the magnitude S of the elastic softening which is proportional to the concentration of the single vacancies [V], For these samples, we also measure the size distribution of the void density by using the infrared lightscattering tomography, to evaluate the concentration [Vc] of the vacancies consumed for the void formation. From these two experiments, we find a sum rale [Vc] + a S= C, where C depends only on the solidification condition and is independent of the thermal history after the solidification. This enables us to find the conservation rale of the vacancies [Vc] + [V] = C. The value of the proportionality constant a in the relation [V] = a S is determined. Demonstration of determining the absolute values of [V] from the measured S is given. An estimate is made for the value of the quadrupole-strain coupling constant.

Keywords: Coupling constants; Different thermal history; Elastic softening; Light-scattering tomography; Low temperatures; Single vacancies; Solidification condition; Vacancy concentration

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Publ.-Id: 21653