Single crystal silicon plate-shaped body

Patent metadata

Field	Value
Publication number	US-10975496-B2
Application number	US-201716315216-A
Country	US
Kind code	B2
Filing date	Jun 30, 2017
Priority date	Jul 6, 2016
Publication date	Apr 13, 2021
Grant date	Apr 13, 2021

Abstract

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.

First claim

The invention claimed is:

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.

Assignees

• Tokuyama Corp

Inventors

• Masada Isao
• Tachibana Shoji

Classifications

• H10F71/121

  The active layers comprising only Group IV materials · CPC title

• C01B33/02 Primary

  Silicon (forming single crystals or homogeneous polycrystalline material with defined structure C30B) · CPC title

• C30B15/00 Primary

  Single-crystal growth by pulling from a melt, e.g. Czochralski method (under a protective fluid C30B27/00) · CPC title

• C30B29/06 Primary

  Silicon · CPC title

• C01P2006/80

  Compositional purity · CPC title