Nitride Semiconductor Growth via Void-Embedded Buffer Layer
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Solution Overview
Problem
Current methods for growing nitride semiconductor layers on hetero-substrates with different materials suffer from lattice constant and thermal expansion coefficient differences, leading to defects and cracks, and involve complex processes that reduce device reliability and increase costs.
Innovation Solution
A method involving the formation of nano-structures on a substrate, followed by the creation of voids in buffer layers without additional mask processes, which mitigates stress and reduces crack occurrence by allowing the nitride semiconductor layer to grow on a compressible buffer layer with embedded voids.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a nitride semiconductor layer is grown on a hetero-substrate with different material, then the device can achieve high breakdown voltage and high temperature stability, but lattice constant difference and thermal expansion coefficient difference cause cracks and defects
Solution Approach 1:
The patent introduces a buffer layer containing voids (porous structure) between the hetero-substrate and nitride semiconductor layer. These voids act as stress-absorbing elements that accommodate the lattice constant and thermal expansion coefficient differences, preventing crack formation while maintaining device reliability.
Solution Approach 2:
The buffer layer with embedded voids is formed in advance before growing the nitride semiconductor layer. This pre-formed cushioning structure absorbs thermal and mechanical stress during subsequent processing and operation, preventing harmful cracks from developing in the semiconductor layer.
2Reliability
If conventional buffer layer methods are used to reduce stress, then crack occurrence is reduced, but the process becomes complex involving additional mask layer formation and patterning
Solution Approach 1:
The patent extracts and removes the complex mask layer formation and patterning steps from the conventional process. Instead of using masks to define buffer layer regions, the invention directly forms the buffer layer with voids through a simplified deposition and etch-back process, significantly reducing process complexity.
Solution Approach 2:
The buffer layer structure is designed to self-form the necessary stress-relief features without requiring external mask patterns. The voids are created through direct etching of the buffer layer material, allowing the structure to serve its own patterning function and eliminating the need for separate mask processes.
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
This approach effectively reduces the occurrence of cracks in nitride semiconductor layers, improves device reliability, and simplifies the growth process by eliminating the need for complex mask layer formation and patterning, thereby reducing costs and enhancing the nitride semiconductor's performance.
Implementation Method 1
mitigates stress and reduces crack occurrence by allowing the nitride semiconductor layer to grow on a compressible buffer layer with embedded voids
Data Source
AI summary
A method of growing a nitride semiconductor layer includes forming a plurality of nano-structures on a substrate, forming a first buffer layer on the substrate such that upper portions of each of the nano-structures are exposed, removing the nano-structures to form voids in the first buffer layer, and growing a nitride semiconductor layer on the first buffer layer including the voids.