Engineered Substrates with Shear Strength Enhancement
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Solution Overview
Problem
Conventional engineered substrates for solid-state transducer (SST) devices face issues with shear strength, leading to defects and shear tear-out during epitaxial growth, which affects the quality and reliability of SST structures.
Innovation Solution
The implementation of a shear strength enhancement material with high shear modulus, such as titanium nitride or tungsten, and a bonding material with oxide-oxide bonding techniques to enhance the shear strength of the substrate, allowing for a robust epitaxial formation structure that bridges defects and resists shear tear-out.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional engineered substrate with low shear strength material (e.g., silicon with Si(1,1,1) crystal orientation) is used, then the substrate is easy to manufacture, but shear tear-out occurs across defects during epitaxial growth
Solution Approach 1:
The patent changes the material parameter from low shear strength silicon (Si(1,1,1)) to high shear strength materials such as silicon carbide (SiC), sapphire (Al2O3), or diamond. This parameter change eliminates shear tear-out during epitaxial growth while maintaining manufacturing feasibility through established semiconductor fabrication processes.
Solution Approach 2:
The patent employs composite substrate structures combining multiple materials with complementary properties. For example, a silicon carbide layer is deposited on a silicon handle wafer, creating a composite structure that leverages the high shear strength of SiC while utilizing the ease of silicon processing for initial fabrication steps.
2Manufacturing precision
If defect mitigation material is applied to cure surface defects, then the surface smoothness is improved, but additional manufacturing steps and complexity are introduced
Solution Approach 1:
The patent applies defect mitigation material (such as spin-on-glass or CMP polishing) to the handle wafer surface before bonding the epitaxial layer. This preliminary action prevents defect propagation during subsequent epitaxial growth, eliminating the need for complex post-processing defect correction steps.
Solution Approach 2:
The patent extracts and removes the handle wafer after the epitaxial growth is complete, leaving only the high-quality epitaxial layer on the final substrate. This extraction eliminates the need to maintain complex multi-layer defect mitigation structures in the final product.
3Reliability
If extensive defect mitigation processes are used, then defect reduction is achieved, but manufacturing costs increase
Solution Approach 1:
The patent changes the fundamental material parameter to high shear strength substrates that inherently resist shear tear-out. This parameter change reduces defect formation at the source, eliminating the need for expensive multi-step defect mitigation processes and reducing overall manufacturing costs.
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 results in an engineered substrate assembly with enhanced shear strength, reducing defects and manufacturing costs by minimizing the need for extensive defect mitigation, and enabling the formation of high-quality SST structures with improved reliability.
Implementation Method 1
a bonding material with oxide-oxide bonding techniques to enhance the shear strength of the substrate
Implementation Method 2
a shear strength enhancement material with high shear modulus, such as titanium nitride or tungsten
Data Source
AI summary
Engineered substrates having epitaxial formation structures with enhanced shear strength and associated systems and methods are disclosed herein. In several embodiments, for example, an engineered substrate can be manufactured by forming a shear strength enhancement material at a front surface of a donor substrate and implanting ions a depth into the donor substrate through the shear strength enhancement material. The ion implantation can form a doped portion in the donor substrate that defines an epitaxial formation structure. The method can further include transferring the epitaxial formation structure from the donor substrate to a front surface of a handle substrate. The shear strength enhancement material can be positioned between the epitaxial formation structure and the front surface of the handle substrate and bridge defects in the front surface of the handle substrate.