Patterned Buried Porous Layer for Heat-Dissipating III-V Substrates
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Solution Overview
Problem
High-power semiconductor devices, such as HEMTs, face strain and cracking due to lattice mismatch between substrate and handle wafer, leading to thermal dissipation issues and device performance degradation.
Innovation Solution
A patterned buried porous layer within the semiconductor substrate is introduced, providing discrete openings for thermal pathways and reducing stress on the III-V semiconductor compound substrate, allowing for improved heat dissipation and device performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a handle wafer is used to support the semiconductor substrate, then mechanical strength is improved, but lattice mismatch causes strain and cracking
Solution Approach 1:
The patent introduces a patterned porous layer that segments the interface between the handle wafer and semiconductor substrate into discrete contact points. This segmentation allows the structure to accommodate lattice mismatch strain while maintaining mechanical support, preventing cracking by distributing stress across multiple isolated regions rather than a continuous interface.
Solution Approach 2:
The patent employs a porous layer as an intermediate structure between the handle wafer and semiconductor substrate. The porous nature of this layer provides mechanical compliance to absorb strain from lattice mismatch while maintaining structural integrity. The porosity allows the layer to deform elastically under stress, preventing crack propagation that would occur in a solid, rigid interface.
2Strength
If the substrate is made thicker to improve mechanical strength, then strength is improved, but thermal dissipation capability deteriorates
Solution Approach 1:
The porous layer serves dual functions: providing mechanical compliance to accommodate lattice mismatch and creating thermal pathways for heat dissipation. The porous structure, when oriented appropriately, allows heat to conduct through the layer via the solid骨架 while the pores can be filled with materials having favorable thermal conductivity or serve as pathways for convective cooling.
Solution Approach 2:
The patent creates a composite structure combining the handle wafer, porous intermediate layer, and semiconductor substrate. This composite design allows optimization of each layer for its specific function: the handle wafer provides mechanical strength, the porous layer provides strain accommodation and thermal management, and the substrate provides device functionality. The composite structure achieves both mechanical strength and thermal dissipation that neither component could achieve alone.
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 solution effectively reduces stress on the substrate, prevents cracking, and enhances thermal dissipation, leading to improved performance and reliability of high-power semiconductor devices operating at higher frequencies.
Implementation Method 1
non-patterned portions of the semiconductor substrate provide a thermal pathway within the semiconductor substrate
Implementation Method 2
a lattice mismatch between the substrate and a handle wafer can result in a strain placed on the substrate
Data Source
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AI summary
A structure comprising a semiconductor substrate; a buried porous semiconductor material; a semiconductor compound material and at least one device on the semiconductor compound material.