Template for epitaxial growth, method for producing the same, and nitride semiconductor device
View Patent ↗The present invention provides a method for producing a template for epitaxial growth, the method including: a surface treatment step of dispersing Ga atoms on a surface of a sapphire substrate; and an AlN growth step of epitaxially growing an AlN layer on the sapphire substrate, wherein in a Ga concentration distribution in a depth direction perpendicular to the surface of the sapphire substrate in an internal region of the AlN layer excluding a near-surface region up to a depth of 100 nm from the surface of the AlN layer, which is obtained by secondary ion mass spectrometry, a position in the depth direction where the Ga concentration takes the maximum value is present in a near-interface region located between the interface of the sapphire substrate and a position at 400 nm spaced apart from the interface to the AlN layer side, and the maximum value of the Ga concentration is 3×10 17 atoms/cm 3 or more and 2×10 20 atoms/cm 3 or less.
1. A method for producing a template having an AlN layer on a surface of a sapphire substrate and used as an underlayer for epitaxially growing a GaN-family compound semiconductor layer, the method comprising:
a surface treatment step of dispersing Ga atoms on a surface of a sapphire substrate; and
an AlN growth step of epitaxially growing an AlN layer on the sapphire substrate,
wherein in a Ga concentration distribution in a depth direction perpendicular to the surface of the sapphire substrate in an internal region of the AlN layer excluding a near-surface region up to a depth of 100 nm from the surface of the AlN layer, which is obtained by secondary ion mass spectrometry,
a position in the depth direction where the Ga concentration takes a maximum value is present in a near-interface region located between the surface of the sapphire substrate and a position at 400 nm spaced apart from the surface of the sapphire substrate to the AlN layer side, and
the maximum value of the Ga concentration is 3×10 17 atoms/cm 3 or more and 2×10 20 atoms/cm 3 or less.
2. The method for producing a template according to claim 1 , wherein a primary ion species used in the secondary ion mass spectrometry is O 2 + .
3. The method for producing a template according to claim 1 , wherein the AlN growth step is started at any of the following timings: after a completion of the surface treatment step, simultaneously with a start of the surface treatment step, or in a middle of the surface treatment step.
4. The method for producing a template according to claim 3 , wherein a primary ion species used in the secondary ion mass spectrometry is O 2 + .
5. The method for producing a template according to claim 1 , wherein in the surface treatment step, a compound as a material of Ga is supplied to a growth chamber for performing the AlN growth step.
6. The method for producing a template according to claim 5 , wherein a primary ion species used in the secondary ion mass spectrometry is O 2 + .
7. The method for producing a template according to claim 5 , wherein the AlN growth step is started at any of the following timings: after a completion of the surface treatment step, simultaneously with a start of the surface treatment step, or in a middle of the surface treatment step.
8. The method for producing a template according to claim 7 , wherein a primary ion species used in the secondary ion mass spectrometry is O 2 +.
9. A template for epitaxial growth comprising:
a sapphire substrate having Ga atoms dispersed on a surface thereof; and
an AlN layer epitaxially grown on the sapphire substrate,
wherein in a Ga concentration distribution in a depth direction perpendicular to the surface of the sapphire substrate in an internal region of the AlN layer excluding a near-surface region up to a depth of 100 nm from the surface of the AlN layer, which is obtained by secondary ion mass spectrometry,
a position in the depth direction where the Ga concentration takes a maximum value is present in a near-interface region located between the surface of the sapphire substrate and a position at 400 nm spaced apart from the surface of the sapphire substrate to the AlN layer side, and
the maximum value of the Ga concentration is 3×10 17 atoms/cm 3 or more and 2×10 20 atoms/cm 3 or less.
10. A nitride semiconductor device comprising:
the template for epitaxial growth according to claim 9 ; and
at least one GaN-family compound semiconductor layer epitaxially grown on the template.
11. The template for epitaxial growth according to claim 9 , wherein a primary ion species used in the secondary ion mass spectrometry is O 2 + .
12. A nitride semiconductor device comprising:
the template for epitaxial growth according to claim 11 ; and
at least one GaN-family compound semiconductor layer epitaxially grown on the template.