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 5 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.
47 Citations
29 Claims
-
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 5 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, 13, 14, 15, 16, 17, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28)
- 0001>
-
12. 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 5 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 5 to about 10 degrees.
- 0001>
-
18. A method of fabricating a microelectronic or opto-electronic device, comprising
(a) 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 5 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 5 to about 10 degrees, and(b) depositing on said GaN substrate a homoepitaxial III–
V nitride material.
- 0001>
-
29. 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 5 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.
- V nitride substrate including a (Al,In,Ga)N (0001) surface offcut from the <
Specification