Diamond single crystal, method for producing the same, and single crystal diamond tool

Patent metadata

Field	Value
Publication number	US-9441312-B2
Application number	US-201314408830-A
Country	US
Kind code	B2
Filing date	Jun 27, 2013
Priority date	Jun 29, 2012
Publication date	Sep 13, 2016
Grant date	Sep 13, 2016

Abstract

A method for producing a diamond single crystal includes implanting an ion other than carbon into a surface of a diamond single crystal seed substrate and thereby decreasing the transmittance of light having a wavelength of 800 nm, the surface having an off-angle of 7 degrees or less with respect to a {100} plane, and homoepitaxially growing a diamond single crystal on the ion-implanted surface of the seed substrate using a chemical vapor synthesis under synthesis conditions where the ratio N C /N H of the number of carbon-containing molecules N C to the number of hydrogen molecules N H in a gas phase is 10% or more and 40% or less, the ratio N N /N C of the number of nitrogen molecules N N to the number of carbon-containing molecules N C in the gas phase is 0.1% or more and 10% or less, and the seed substrate temperature T is 850° C. or more and less than 1000° C.

First claim

The invention claimed is:

1. A diamond single crystal synthesized using a chemical vapor synthesis method and having an absorption coefficient of 35 cm −1 or more and 80 cm −1 or less for light having a wavelength of 350 nm.

2. The diamond single crystal according to claim 1 , wherein the absorption coefficient is 35 cm −1 or more and 64 cm −1 or less.

3. A diamond single crystal produced by gas-phase synthesis,
wherein the diamond single crystal includes two or more diamond monocrystalline layers having different absorption coefficients for light having a wavelength of 350 nm,
one of the diamond monocrystalline layers having one main surface has an absorption coefficient of less than 25 cm −1 for light having a wavelength of 350 nm, and another of the diamond monocrystalline layers having the other main surface has an absorption coefficient of 25 cm −1 or more and 80 cm −1 or less for light having a wavelength of 350 nm, and
any of the two or more diamond monocrystalline layers has an absorption coefficient of 80 cm −1 or less for light having a wavelength of 350 nm.

4. The diamond single crystal according to claim 3 , wherein the diamond single crystal includes two or more diamond monocrystalline layers, and the absorption coefficient for light having a wavelength of 350 nm increases monotonically from the diamond monocrystalline layer having one main surface and having an absorption coefficient of less than 25 cm −1 for light having a wavelength of 350 nm to the diamond monocrystalline layer having the other main surface and having an absorption coefficient of 25 cm −1 or more and 80 cm −1 or less for light having a wavelength of 350 nm.

5. A method for producing a diamond single crystal, comprising:
implanting an ion other than carbon into a main surface of a diamond single crystal seed substrate and thereby decreasing the transmittance of light having a wavelength of 800 nm, the main surface having an off-angle of 7 degrees or less with respect to a {100} plane; and
homoepitaxially growing a diamond single crystal on the ion-implanted main surface of the seed substrate using a chemical vapor synthesis method under synthesis conditions where the ratio NC/N H of the number of carbon-containing molecules N C to the number of hydrogen molecules N H in a gas phase is 10% or more and 40% or less, the ratio N N /N C of the number of nitrogen molecules N N to the number of carbon-containing molecules N C in the gas phase is 0.1% or more and 10% or less, and the seed substrate temperature T is 850° C. or more and less than 1000° C.

6. The method for producing a diamond single crystal according to claim 5 , further comprising: homoepitaxially growing a diamond single crystal on the growth surface, on which the diamond single crystal has been homoepitaxially grown, using a chemical vapor synthesis method under synthesis conditions where either the ratio N C /N H of the number of carbon-containing molecules N C to the number of hydrogen molecules N H in a gas phase is more than 0% and less than 10% or the ratio N N /N C of the number of nitrogen molecules N N to the number of carbon-containing molecules N C is less than 0.1%, and the seed substrate temperature T is less than 1000° C.

7. The method for producing a diamond single crystal according to claim 5 , wherein the off-angle is 3 degrees or less.

8. The method for producing a diamond single crystal according to claim 5 , further comprising separating the seed substrate from the diamond single crystal homoepitaxially grown on the seed substrate.

9. A single crystal diamond tool, comprising a cutting edge made of the diamond single crystal according to claim 3 , wherein the cutting edge has a rake face formed of a main surface of the diamond single crystal, and the main surface has an absorption coefficient of less than 25 cm −1 for light having a wavelength of 350 nm.

10. A single crystal diamond tool, comprising a diamond single crystal joined to a shank of the tool, wherein the diamond single crystal includes an ion-implanted layer formed by ion implantation into a crystal face on a side of the diamond single crystal to be joined to the shank.

11. The single crystal diamond tool according to claim 10 , wherein the single crystal diamond tool is a single crystal diamond cutting tool.

12. The single crystal diamond tool according to claim 10 , wherein the transmittance of light having a wavelength of 800 nm in a direction perpendicular to the ion-implanted layer in the diamond single crystal having the ion-implanted layer changes 10% or more due to removal of the ion-implanted layer.

13. The single crystal diamond tool according to claim 10 , wherein the diamond single crystal before the ion implantation has an absorption coefficient of 25 cm −1 or more and 80 cm −1 or less for light having a wavelength of 350 nm in a direction perpendicular to a face of the diamond single crystal on which the ion-implanted layer is to be formed.

Assignees

• Sumitomo Electric Industries

Inventors

• Ueda Akihiko
• Nishibayashi Yoshiki
• Sumiya Hitoshi

Classifications

• B23B2226/31

  Diamond · CPC title

• Y10T428/30

  Self-sustaining carbon mass or layer with impregnant or other layer · CPC title

• C30B25/20

  the substrate being of the same materials as the epitaxial layer · CPC title

• C30B31/22

  by ion-implantation · CPC title

• B23B27/148

  Composition of the cutting inserts · CPC title