Quantitative evaluation device and method of atomic vacancy existing in silicon wafer

A method for quantitatively evaluating atomic vacancy existing in a silicon wafer, which comprises:

• oscillating an ultrasonic pulse onto a silicon sample cut out from a given site of a silicon wafer and directly provided on its surface with a thin-film transducer having properties capable of following an expansion associated with a temperature drop of the silicon sample at a temperature region of not higher than 25 K at a state of applying an exterior magnetic field, if necessary, while cooling at the temperature region;
• propagating the oscillated ultrasonic pulse into the silicon sample;
• detecting a change of sonic velocity in the propagated ultrasonic pulse;
• calculating a reducing quantity of an elastic constant associated with the drop of the cooling temperature from the change of sonic velocity;
• and
• quantitatively evaluating a kind and a concentration of an atomic vacancy existing in the silicon wafer from the calculated reducing quantity of elastic constant;
• wherein the thin-film transducer has a C-axis inclined at an angle of 5-60°with respect to the surface of the silicon sample, and measures at least a transverse wave component among a vertical wave component and a transverse wave component propagated and detected in the silicon sample.

A device for quantitatively evaluating atomic vacancy existing in a silicon wafer, which comprises:

• a magnetic force generator applying an external magnetic field to a silicon sample cut out from a given site of a silicon wafer,
• a temperature controller cooling the silicon sample to a temperature region of not higher than 50 K,
• an ultrasonic oscillator oscillating an ultrasonic pulse to the surface of the silicon sample and propagating the oscillated ultrasonic pulse into the silicon sample and detecting a change of sound velocity in the propagated ultrasonic pulse, wherein a thin-film transducer having properties capable of following an expansion of the silicon sample associated with a temperature drop at the above temperature region and substantially aligning C-axis in a given direction is directly formed on the surface of the silicon sample;
• wherein the thin-film transducer has a C-axis inclined at an angle of 5-60°with respect to the surface of the silicon sample, and measures at least a transverse wave component among a vertical wave component and a transverse wave component propagated and detected in the silicon sample.