Single crystal silicon plate-shaped body
A single crystal silicon plate-shaped body as cut out from an upper portion of a straight body portion of a CZ method single crystal silicon ingot has an interstitial oxygen concentration in a crystal is 25 ppma to 45 ppma and a substitutional carbon concentration is 0.5 ppma or less in a radial center. In the radial center, oxygen precipitates are not observed in a bulk in an image of 200,000 times by a transmission electron microscope, and after heating the single crystal silicon plate-shaped body at 950° C. for 60 minutes, oxygen precipitates are observed in an image of the 200,000 times, and a shape of the oxygen precipitates is observed in a polyhedral structure in an image of 2,000,000 times.
1. A single crystal silicon plate-shaped body, wherein
an interstitial oxygen concentration in a crystal is 25 ppma to 45 ppma and a substitutional carbon concentration is 0.5 ppma or less in a radial center, and
in the radial center, oxygen precipitates are not observed in a bulk in an image of 200,000 times by a transmission electron microscope, and
after heating the single crystal silicon plate-shaped body at 950° C. for 60 minutes, oxygen precipitates are observed with number density of 1.0×10 11 to 2×10 12 pieces/cm 3 , and
when the oxygen precipitates are observed in an image of 2,000,000 times, oxygen precipitates of which a shape is observed in a polyhedral structure are 75% or more.
2. The single crystal silicon plate-shaped body according to claim 1 , wherein the substitutional carbon concentration is 0.001 ppma to 0.3 ppma.
3. The single crystal silicon plate-shaped body according to claim 1 , wherein the single crystal silicon plate-shaped body is quarried from a CZ method single crystal silicon ingot and is not subjected to thermal history at 900° C. or higher after quarrying.
4. The single crystal silicon plate-shaped body according to claim 3 , wherein the single crystal silicon plate-shaped body is quarried from an upper portion of a straight body portion of the CZ method single crystal silicon ingot.
5. The single crystal silicon plate-shaped body according to claim 1 , wherein the polyhedral structure is an octahedron.
6. The single crystal silicon plate-shaped body according to claim 1 , wherein the number density of oxygen precipitates is calculated by:
confirming substantially all distortions in an image at 200,000 times are oxygen precipitates; and
measuring a number density of distortions at 10,000-50,000 times which are observed as black dots, wherein the number density of distortions is the number density of oxygen precipitates.
7. The single crystal silicon plate-shaped body according to claim 1 , wherein the number density of oxygen precipitates is calculated by:
confirming distortions in an image at 200,000 times are oxygen precipitates and defects;
measuring a number density of distortions at 10,000-50,000 times which are observed as black dots; and
multiplying a proportion of oxygen precipitates among the confirmed distortions by the measured number density of black dots.
8. A CZ method single crystal silicon ingot comprising:
a region which satisfies properties of the single crystal silicon plate-shaped body according to claim 1 in a long axis direction of the ingot.
9. A single crystal silicon ingot, comprising:
a region which satisfies properties of the single crystal silicon plate-shaped body according to claim 1 in an upper portion of a straight body portion.
10. A single crystal silicon body, comprising:
a single crystal silicon body having an interstitial oxygen concentration of 30 ppma to 45 ppma and a substitutional carbon concentration of 0.001 ppma to 0.5 ppma in a radial center, and
oxygen precipitates having a number density of 1.0×10 11 to 2×10 12 pieces/cm 3 in the radial center, wherein 75% or more of the oxygen precipitates have a polyhedral structure when observed in an image of 2,000,000 times by a transmission electron microscope.