Vicinal gallium nitride substrate for high quality homoepitaxy
First Claim
1. A GaN substrate including a GaN (0001) surface offcut from the <
- 0001>
direction predominantly towards a direction selected from the group consisting of <
10{overscore (1)}0> and
<
11{overscore (2)}0>
directions, at an offcut angle in a range that is from about 0.2 to about 10 degrees, wherein said surface has a RMS roughness measured by 50×
50 μ
m2 AFM scan that is less than 1 nm, and a dislocation density that is less than 3E6 cm−
2.
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Accused Products
Abstract
A III-V nitride, e.g., GaN, substrate including a (0001) surface offcut from the <0001> direction predominantly toward a direction selected from the group consisting of <10-10> and <11-20> directions, at an offcut angle in a range that is from about 0.2 to about 10 degrees, wherein the surface has a RMS roughness measured by 50×50 μm2 AFM scan that is less than 1 nm, and a dislocation density that is less than 3E6 cm−2. The substrate may be formed by offcut slicing of a corresponding boule or wafer blank, by offcut lapping or growth of the substrate body on a corresponding vicinal heteroepitaxial substrate, e.g., of offcut sapphire. The substrate is usefully employed for homoepitaxial deposition in the fabrication of III-V nitride-based microelectronic and opto-electronic devices.
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Citations
39 Claims
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1. A GaN substrate including a GaN (0001) surface offcut from the <
- 0001>
direction predominantly towards a direction selected from the group consisting of <
10{overscore (1)}0> and
<
11{overscore (2)}0>
directions, at an offcut angle in a range that is from about 0.2 to about 10 degrees, wherein said surface has a RMS roughness measured by 50×
50 μ
m2 AFM scan that is less than 1 nm, and a dislocation density that is less than 3E6 cm−
2. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 23, 24, 25, 26, 27, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38)
- 0001>
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22. A method of forming a GaN substrate including a GaN (0001) surface offcut from the <
- 0001>
direction predominantly towards a direction selected from the group consisting of <
10{overscore (1)}0> and
<
11{overscore (2)}0>
directions, at an offcut angle in a range that is from about 0.2 to about 10 degrees, wherein said surface has a RMS roughness measured by 50×
50 μ
m2 AFM scan that is less than 1 nm, and a dislocation density that is less than 3E6 cm−
2, said method including growing a bulk GaN single crystal body, and processing said bulk GaN single crystal body to form at least one wafer therefrom, wherein said processing step includes a step selected from the group consisting of;
(i) a slicing step conducted in a slicing plane tilted away from the c-plane at said offcut angle in said direction selected from the group consisting of <
10{overscore (1)}0> and
<
11{overscore (2)}0>
directions, (ii) an angle lapping step conducted in a lapping plane tilted away from the c-plane at said offcut angle in said direction selected from the group consisting of <
10{overscore (1)}0> and
<
11{overscore (2)}0>
directions, and (iii) separating said bulk GaN single crystal body after growing said bulk GaN single crystal body on a vicinal heteroepitaxial substrate including a (0001) surface offcut from the <
0001>
direction predominantly towards a direction selected from the group consisting of <
10{overscore (1)}0> and
<
11{overscore (2)}0>
directions, at an offcut angle in said range of from about 0.2 to about 10 degrees.
- 0001>
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28. A method of fabricating a microelectronic or opto-electronic device, comprising
(c) forming a GaN substrate including a GaN (0001) surface offcut from the < - 0001>
direction predominantly towards a direction selected from the group consisting of <
10{overscore (1)}0> and
<
11{overscore (2)}0>
directions, at an offcut angle in a range that is in a range of from about 0.2 to about 10 degrees, wherein said surface has a RMS roughness measured by 50×
50 μ
m AFM scan that is less than 1 nm, and a dislocation density that is less than 3E6 cm−
2, said method including growing a bulk GaN single crystal body, and processing said bulk GaN single crystal body to form at least one wafer therefrom, wherein said processing step includes a step selected from the group consisting of;
(i) a slicing step conducted in a slicing plane tilted away from the c-plane at said offcut angle in said direction selected from the group consisting of <
10{overscore (1)}0> and
<
11{overscore (2)}0>
directions, (ii) an angle lapping step conducted in a lapping plane tilted away from the c-plane at said offcut angle in said direction selected from the group consisting of <
10{overscore (1)}0> and
<
11{overscore (2)}0>
directions, and (iii) separating said bulk GaN single crystal body after growing said bulk GaN single crystal body on a vicinal heteroepitaxial substrate including a (0001) surface offcut from the <
0001>
direction predominantly towards a direction selected from the group consisting of <
10{overscore (1)}0> and
<
11{overscore (2)}0>
directions, at an offcut angle in said range of from about 0.2 to about 10 degrees, and(d) depositing on said GaN substrate a homoepitaxial III-V nitride material.
- 0001>
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39. A III-V nitride substrate including a (Al,In,Ga)N (0001) surface offcut from the <
- 0001>
direction predominantly towards a direction selected from the group consisting of <
10{overscore (1)}0> and
<
11{overscore (2)}0>
directions, at an offcut angle in a range that is from about 0.2 to about 10 degrees, wherein said surface has a RMS roughness measured by 50×
50 μ
m2 AFM scan that is less than 1 nm, and a dislocation density that is less than 3E6 cm−
2.
- 0001>
Specification