Patent ID: 8578777

Claim:
A quantitative evaluation method comprising steps of: oscillating, in a state in which an external magnetic field is applied to a silicon wafer while keeping the silicon wafer at a constant temperature, an ultrasonic wave pulse and receiving a measurement wave pulse obtained after the ultrasonic wave pulse is propagated through the silicon wafer for detecting a phase difference between the ultrasonic wave pulse and the measurement wave pulse; and calculating an elastic constant from the phase difference, wherein the external magnetic field is changed in a constant temperature state to measure an amount of the elastic constant changed corresponding to a change in the external magnetic field for evaluating a concentration of atomic vacancies in the silicon wafer, based on a relationship ⁢ C ⁢ ⁢ ( T , H ) = C T 0 - Ng 2 ⁢ χ ⁡ ( T , H ) 1 - g ′ ⁢ χ ⁡ ( T , H ) χ ⁡ ( T , H ) = 1 k B ⁢ T ⁢ ∑ i ⁢ O ii ⁡ ( H ) ⁢ exp ⁡ ( - E j ⁡ ( H ) / k B ⁢ T ) ∑ i ⁢ exp ⁡ ( - E i ⁡ ( H ) / k B ⁢ T ) - 2 ⁢ ∑ ij ⁢ ∑ i ≠ j ⁢ O ij ⁡ ( H ) E i - E j ⁢ exp ⁡ ( - E j ⁡ ( H ) / k B ⁢ T ) ∑ i ⁢ exp ⁡ ( - E i ⁡ ( H ) / k B ⁢ T ) wherein C(T,H) is an elastic constant, N is a concentration of atomic vacancies, C 0 T is a background, g is a coupling constant of a quadrupole distortion interaction, g′ is a coupling constant of an interaction between quadrupoles, T is a temperature, H is an external magnetic field, kB is a Boltzmann constant, E(H) is energy level in a quantum state, and O(H) is a quadrupole in a quantum state.