Nitride Semiconductor Substrate Curved (0001) Plane
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Solution Overview
Problem
Nitride semiconductor substrates with curved (0001) planes often exhibit wide off-angle distributions, leading to deteriorated surface morphology and uneven light emission in semiconductor devices, particularly affecting Schottky barrier diodes and light emitting devices.
Innovation Solution
A nitride semiconductor substrate with a (0001) plane curved in a concave spherical shape, where the radius of curvature and off-angle distribution are selectively controlled by varying the curvature in different directions, allowing for a larger radius of curvature and narrower off-angle distribution, thereby improving surface morphology and light emission consistency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the (0001) plane is curved in a concave spherical shape with a small radius of curvature, then the substrate can be manufactured, but the off-angle distribution becomes wide causing surface morphology deterioration
Solution Approach 1:
The invention applies controlled spherical curvature to the (0001) plane of the nitride semiconductor substrate. By precisely controlling the radius of curvature to be 10 m or more, the substrate maintains a concave spherical shape that narrows the off-angle distribution and prevents surface morphology deterioration while remaining manufacturable.
Solution Approach 2:
The invention changes the curvature parameter of the (0001) plane from a conventional small radius to a large radius of 10 m or more. This parameter change directly narrows the off-angle distribution and improves surface morphology, resolving the contradiction between manufacturability and precision.
2Reliability
If the radius of curvature of the (0001) plane is small, then the substrate structure is compact, but the off-angle distribution widens causing uneven light emission
Solution Approach 1:
The invention utilizes a concave spherical shape with a large radius of curvature (10 m or more) for the (0001) plane. This spherical geometry with controlled radius narrows the off-angle distribution across the substrate surface, ensuring uniform light emission and improving device reliability.
Solution Approach 2:
The invention changes the radius of curvature parameter from a small value to 10 m or more. This parameter modification directly addresses the off-angle distribution issue and ensures uniform light emission characteristics while maintaining the necessary substrate structure.
3Manufacturing precision
If the off-angle distribution is wide, then various crystal orientations are present, but surface morphology and light emission properties deteriorate
Solution Approach 1:
The invention changes the curvature radius parameter to 10 m or more, which narrows the off-angle distribution and ensures uniform crystal orientation across the substrate. This parameter change improves surface morphology while maintaining adequate crystal orientation consistency for device performance.
Data Source
AI summary
To provide a technique of increasing a radius of curvature of (0001) plane, and narrowing an off-angle distribution, there is provided a nitride semiconductor substrate containing a group III nitride semiconductor crystal and having a main surface in which a nearest low index crystal plane is (0001) plane, wherein (0001) plane in one of a direction along <1-100> axis and a direction along <11-20> axis orthogonal to the <1-100> axis, is curved in a concave spherical shape with respect to the main surface, and a radius of curvature of the (0001) plane in one of the direction along the <1-100> axis and the direction along the <11-20> axis orthogonal to the <1-100> axis is different from a radius of curvature of at least a part of the (0001) plane in the other direction.