GaN-on-Silicon Wafer Chamfer Geometry for Crown Suppression
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Solution Overview
Problem
Existing methods for preventing crown formation in GaN heteroepitaxial growth on silicon substrates are costly and ineffective in reducing stress-induced cracking, leading to device defects and reduced yield.
Innovation Solution
A group-III nitride semiconductor wafer with a chamfering angle of 21° to 23° and a chamfering width of 500 μm to 1000 μm is used to suppress crown height, reducing substrate cracking and maintaining a sufficient effective area for device fabrication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If chamfering angle is changed from standard 22° to prevent crowns, then crown generation is suppressed, but manufacturing cost increases due to process changes
Solution Approach 1:
The patent applies parameter changes by optimizing the chamfering angle to a specific range (20° to 25°) to suppress crown generation while maintaining compatibility with existing manufacturing processes. This parameter optimization resolves the contradiction by finding a value range that achieves the desired effect without requiring costly process changes.
2Strength
If chamfering width is increased to suppress crown height, then substrate cracking is reduced, but effective device area decreases
Solution Approach 1:
The patent applies parameter changes by optimizing the chamfering width to a specific range (500 μm to 1000 μm) that balances two competing requirements: suppressing crown height to prevent substrate cracking while preserving sufficient effective device area. This optimized parameter range resolves the contradiction by achieving both goals simultaneously.
3Productivity
If chamfering parameters are optimized to prevent crowns, then device yield increases, but stress-induced cracking is not sufficiently reduced
Solution Approach 1:
The patent applies parameter changes by simultaneously optimizing both chamfering angle (20° to 25°) and chamfering width (500 μm to 1000 μm) within specific ranges. This dual parameter optimization resolves the contradiction by achieving both high device yield through crown prevention and sufficient stress-induced cracking resistance through appropriate chamfering dimensions.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The proposed solution effectively lowers crown height, preventing substrate cracking and ensuring high yield and suitability for high-frequency, high-output devices.
Implementation Method 1
a chamfering angle (θ1) relative to the surface of the substrate is 21° or more and 23° or less, and a chamfering width (X1) is 500 μm or more and 1000 μm or less... effectively lowers crown height, preventing substrate cracking
Data Source
AI summary
The present invention is a group-III nitride semiconductor wafer including a group-III nitride semiconductor film on a substrate for film formation, in which in a cross-sectional shape of a surface of the substrate for film formation of a chamfered portion of the substrate in a diameter direction, a chamfering angle (θ1) relative to the surface of the substrate is 21° or more and 23° or less, and on the surface of the substrate in a diameter direction, a chamfering width (X1) is 500 μm or more and 1000 μm or less, which is a distance between an outer peripheral end portion of the substrate for film formation and an inner peripheral end portion of the chamfered portion. Thereby, the group-III nitride semiconductor wafer, in which the group-III nitride semiconductor film is provided on the substrate for film formation, and the method for producing the same are provided.