Crystal laminate, semiconductor device and method for manufacturing the same

Patent metadata

Field	Value
Publication number	US-11640906-B2
Application number	US-201816617799-A
Country	US
Kind code	B2
Filing date	Apr 19, 2018
Priority date	May 29, 2017
Publication date	May 2, 2023
Grant date	May 2, 2023

Abstract

Provided is a crystal laminate including: a crystal substrate formed from a monocrystal of group III nitride expressed by a compositional formula In x Al y Ga 1-x-y N (where 0≤x≤1, 0≤y≤1, 0≤x+y≤1), the crystal substrate containing at least any one of n-type impurity selected from the group consisting of Si, Ge, and O; and a crystal layer formed by a group III nitride crystal epitaxially grown on a main surface of the crystal substrate, at least any one of p-type impurity selected from the group consisting of C, Mg, Fe, Be, Zn, V, and Sb being ion-implanted in the crystal layer. The crystal laminate is configured in a manner such that an absorption coefficient of the crystal substrate for light with a wavelength of 2000 nm when the crystal substrate is irradiated with the light falls within a range of 1.8 cm −1 or more and 4.6 cm −1 or less under a temperature condition of normal temperature.

First claim

The invention claimed is:

1. A crystal laminate comprising:
a crystal substrate formed from a monocrystal of group III nitride expressed by a compositional formula In x Al y Ga 1-x-y N (where 0≤x≤1, 0≤y≤1, 0≤x+y≤1), the crystal substrate containing at least any one of n-type impurity selected from the group consisting of Si, Ge, and O; and
a crystal layer formed by a group III nitride crystal epitaxially grown on a main surface of the crystal substrate, the crystal layer containing at least any one of p-type impurity selected from the group consisting of C, Mg, Fe, Be, Zn, V, and Sb, wherein a concentration of B in the crystal substrate is lower than 1×10 15 at ·cm −3 , and
the crystal laminate is configured in a manner such that an absorption coefficient of the crystal substrate for light with a wavelength of 2000 nm when the crystal substrate is irradiated with the light falls within a range of 1.8 cm −1 or more and 4.6 cm −1 or less under a temperature condition of normal temperature.

2. The crystal laminate of claim 1 , wherein
density of an intrinsic carrier within the crystal substrate is lower than 1×10 17 cm −3 at least under a temperature condition of normal temperature or higher and 1250° C. or lower.

3. The crystal laminate of claim 2 , wherein
concentration of a free electron occurring within the crystal substrate due to addition of the n-type impurity is 1×10 18 cm −3 or more and 2.5×10 18 cm −3 or less under a temperature condition of normal temperature.

4. The crystal laminate of claim 2 , wherein
concentration of the n-type impurity in the crystal substrate is 1×10 18 at·cm −3 or more and 2.5×10 18 at·cm −3 or less.

5. The crystal laminate of claim 2 , wherein
concentration of O in the crystal substrate is 1×10 17 at·cm −3 or less and total concentration of Si and Ge in the crystal substrate is 1×10 18 at·cm −3 or more and 2.5×10 18 at·cm −3 or less.

6. The crystal laminate of claim 1 , wherein
concentration of a free electron occurring within the crystal substrate due to addition of the n-type impurity is 1×10 18 cm −3 or more and 2.5×10 18 cm −3 or less under a temperature condition of normal temperature.

7. The crystal laminate of claim 6 , wherein
concentration of the n-type impurity in the crystal substrate is 1×10 18 at·cm −3 or more and 2.5×10 18 at·cm −3 or less.

8. The crystal laminate of claim 6 , wherein
concentration of O in the crystal substrate is 1×10 17 at·cm −3 or less and total concentration of Si and Ge in the crystal substrate is 1×10 18 at·cm −3 or more and 2.5×10 18 at·cm −3 or less.

9. The crystal laminate of claim 1 , wherein
concentration of the n-type impurity in the crystal substrate is 1×10 18 at·cm −3 or more and 2.5×10 18 at·cm −3 or less.

10. The crystal laminate of claim 9 , wherein
concentration of O in the crystal substrate is 1×10 17 at·cm −3 or less and total concentration of Si and Ge in the crystal substrate is 1×10 18 at·cm −3 or more and 2.5×10 18 at·cm −3 or less.

11. The crystal laminate of claim 1 , wherein
concentration of O in the crystal substrate is 1×10 17 at·cm −3 or less and total concentration of Si and Ge in the crystal substrate is 1×10 18 at·cm −3 or more and 2.5×10 18 at·cm −3 or less.

12. A semiconductor device comprising:
a crystal substrate formed from a monocrystal of group III nitride expressed by a compositional formula In x Al y Ga 1-x-y N (where 0≤x≤1, 0≤y≤1, 0≤x+y≤1), the crystal substrate containing at least any one of n-type impurity selected from the group consisting of Si, Ge, and O; and
a crystal layer formed by a group III nitride crystal epitaxially grown on a main surface of the crystal substrate, the crystal layer containing at least any one of p-type impurity selected from the group consisting of C, Mg, Fe, Be, Zn, V, and Sb, wherein a concentration of B in the crystal substrate is lower than 1×10 15 at·cm −3 , and
the semiconductor device is configured in a manner such that an absorption coefficient of the crystal substrate for light with a wavelength of 2000 nm when the crystal substrate is irradiated with the light falls within a range of 1.8 cm −1 or more and 4.6 cm −1 or less under a temperature condition of normal temperature.

13. A semiconductor device manufacturing method comprising:
preparing a crystal laminate comprising a crystal substrate formed from a monocrystal of group III nitride expressed by a compositional formula In x Al y Ga 1-x-y N (where 0≤x≤1, 0≤y≤1, 0≤x+y≤1), the crystal substrate containing at least any one of n-type impurity selected from the group consisting of Si, Ge, and O, and a crystal layer formed by a group III nitride crystal epitaxially grown on a main surface of the crystal substrate, wherein a concentration of B in the crystal substate is lower than 1+10 15 at·cm −3 , and an absorption coefficient of the crystal substrate for light with a wavelength of 2000 nm when the crystal substrate is irradiated with the light is 1.8 cm −1 or more and 4.6 cm −1 or less under a temperature condition of normal temperature;
ion-implanting at least any one of p-type impurity selected from the group consisting of C, Mg, Fe, Be, Zn, V, and Sb in a main surface of the crystal layer; and
heating the crystal laminate by irradiating the crystal laminate with an infrared ray.

14. The semiconductor device manufacturing method of claim 13 , wherein
the heating of the crystal laminate is performed in a condition in which a support-receiving surface of the crystal laminate is being supported at three or more locations and the crystal laminate and a retaining plate present on the support-receiving surface side of the crystal laminate are separate from each other.

15. The semiconductor device manufacturing method of claim 13 , wherein
the preparation of the crystal laminate includes a crystal growth process of loading a seed crystal substrate and a raw material including a group III element in a reaction vessel, and supplying a nitriding agent and a halide of the raw material onto the seed crystal substrate heated to a predetermined crystal growth temperature to grow a crystal of a nitride of the group III element on the seed crystal substrate, and
in the crystal growth process,
a member formed from a material in which at least a surface of the material does not contain quartz and boron is used as a member defining a high-temperature region, at least, of the reaction vessel, the high-temperature region being a region that is heated to the crystal growth temperature and that comes into contact with gas being supplied onto the seed crystal substrate.

Assignees

• Sumitomo Chemical Co
• Univ Hosei

Inventors

• Horikiri Fumimasa
• Yoshida Takehiro
• Mishima Tomoyoshi

Classifications

• H10P30/20

  into semiconductor materials, e.g. for doping · CPC title

• H10P14/20 Primary

  of semiconductor materials · CPC title

• H10P95/904

  of Group III-V semiconductors · CPC title

• H10P34/422

  using incoherent radiation · CPC title

• H10P30/206

  into Group III-V semiconductors · CPC title