Nitride Semiconductor Tension Layer for Silicon Substrates
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Solution Overview
Problem
The production of nitride compound semiconductor components on silicon substrates is challenging due to large thermal expansion differences, leading to tensile stresses, and existing methods are complex and costly, with high defect densities.
Innovation Solution
A method involving a silicon substrate with a nucleation layer of aluminum-containing nitride, a tension layer structure with an Al(Ga)N interlayer and a 3D AlGaN layer grown using metal-organic vapor phase epitaxy, which generates compressive stress and reduces dislocation density without the need for a masking layer, thereby counteracting tensile stresses and simplifying the production process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If nitride compound semiconductors are grown onto silicon substrates, then production costs are reduced, but large tensile stresses are generated due to thermal expansion differences
Solution Approach 1:
A multi-layer tension layer structure is introduced as an intermediary between the silicon substrate and the functional nitride compound semiconductor layer. This structure includes an AlN nucleation layer, AlGaN buffer layer, GaN layer, and AlN capping layer, which collectively manage the thermal expansion mismatch and reduce tensile stresses while enabling cost-effective silicon substrate usage.
Solution Approach 2:
The tension layer structure employs composite material design with alternating layers of different nitride compounds (AlN, AlGaN, GaN) having different lattice constants and thermal expansion coefficients. This composite structure creates a gradient that progressively manages the stress from the silicon substrate while maintaining crystal quality for device fabrication.
2Stress or pressure
If existing tension layer structures with masking layers are used, then compressive stress is generated, but production complexity and costs increase
Solution Approach 1:
The masking layer, which is an unnecessary and complex component in conventional approaches, is completely removed from the structure. The patent achieves the desired compressive stress and defect reduction functionality through a simplified four-layer tension layer structure consisting only of nitride compound semiconductor layers, eliminating the need for masking materials and their associated processing steps.
Solution Approach 2:
The invention changes the compositional parameters of the tension layer structure by using a specific sequence of nitride compounds with varying aluminum content (AlN-AlGaN-GaN-AlN). This parameter variation in composition and lattice constant enables the structure to generate compressive stress and reduce dislocation density without requiring masking layers, thereby simplifying production.
3Reliability
If conventional growth substrates like sapphire, GaN, or SiC are used, then high quality nitride compound semiconductors are grown, but production costs increase
Solution Approach 1:
The multi-layer tension layer structure acts as an intermediary that enables the use of inexpensive silicon substrates to produce high-quality nitride compound semiconductors. The structure compensates for the poor lattice match between silicon and GaN, achieving crystal quality comparable to growth on expensive sapphire, SiC, or GaN substrates while dramatically reducing production costs.
4Stress or pressure
If the thermal expansion difference between silicon and nitride compound semiconductors is considered, then stress management becomes necessary, but process complexity increases
Solution Approach 1:
The invention addresses thermal expansion stress by changing the compositional parameters of the tension layer structure. The specific sequence of nitride compounds with varying aluminum content creates a lattice constant gradient that manages thermal stress during cooling from growth temperature to room temperature, achieving effective stress management through material composition control rather than complex process steps.
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 achieves a nitride compound semiconductor component with low defect density and compressive stress, reducing production complexity and costs, while maintaining the effectiveness of the semiconductor component.
Implementation Method 1
a nucleation layer including an aluminum-containing nitride compound semiconductor is grown onto the growth substrate
Implementation Method 2
a tension layer structure with an Al(Ga)N interlayer and a 3D AlGaN layer grown using metal-organic vapor phase epitaxy
Implementation Method 3
an Al(Ga)N interlayer for generating a compressive stress is disposed between the first GaN semiconductor layer and the second GaN semiconductor layer
Implementation Method 4
in the course of cooling of the layer system from the growth temperature of more than 1000° C. used for growth of nitride compound semiconductors to room temperature, large tensile stresses are generated in the GaN
Data Source
AI summary
A method for producing a nitride compound semiconductor component is disclosed. In an embodiment the method includes providing a growth substrate, growing a nucleation layer of an aluminum-containing nitride compound semiconductor onto the growth substrate, growing a tension layer structure for generating a compressive stress, wherein the tension layer structure comprises at least a first GaN semiconductor layer and a second GaN semiconductor layer, and wherein an Al(Ga)N interlayer for generating the compressive stress is disposed between the first GaN semiconductor layer and the second GaN semiconductor layer and growing a functional semiconductor layer sequence of the nitride compound semiconductor component onto the tension layer structure, wherein a growth of the second GaN semiconductor layer is preceded by a growth of a first 3D AlGaN layer on the Al(Ga)N interlayer in such a way that it has nonplanar structures.