IGBT Thermal Conduction Structure Using SiC Sidewall Isolation
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Solution Overview
Problem
IGBTs face challenges with heat dissipation due to high current usage, leading to performance degradation and increased risk of chip breakage during fabrication, especially in vertical structures, and require expensive silicon-on-insulator substrates for effective isolation.
Innovation Solution
The implementation of a semiconductor IGBT design featuring a high thermal conductivity region made of silicon carbide with a non-planar structure, which includes a bottom and sidewall portion, and an isolation region of silicon dioxide, allowing for efficient heat dissipation and isolation without the need for expensive substrates, while electrodes are positioned on the top surface to simplify the fabrication process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a vertical structure is used for IGBT fabrication, then integration density is improved, but thermal resistance increases leading to heat dissipation problems
Solution Approach 1:
The patent employs a composite structure combining silicon substrate with silicon carbide (SiC) thermal management layer. The SiC material, known for its superior thermal conductivity, is integrated into the IGBT device structure to create a composite thermal management system that effectively addresses the heat dissipation challenge in vertical IGBT configurations.
Solution Approach 2:
The patent introduces an additional thermal management dimension by integrating a dedicated thermal path through the silicon carbide region that operates independently from the electrical current path. This dimensional separation allows heat to be conducted away through a specialized thermal conduit while maintaining the vertical electrical structure for high integration density.
2Reliability
If silicon-on-insulator substrates are used for isolation, then device isolation is improved, but manufacturing cost increases
Solution Approach 1:
The patent extracts the isolation function from the expensive silicon-on-insulator substrate and implements it through a simplified silicon dioxide isolation layer formed directly on the silicon substrate. This extraction of the isolation function allows the use of standard silicon substrates instead of costly SOI substrates while maintaining effective device isolation.
Solution Approach 2:
The patent replaces the expensive silicon-on-insulator substrate with a more economical silicon substrate combined with a thin silicon dioxide isolation layer. This substitution uses cheaper materials to achieve the same isolation effect, significantly reducing manufacturing costs while maintaining device performance.
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 design enhances heat dissipation, prevents rapid temperature rise during operation, and maintains ideal performance for IGBTs and nearby devices, while avoiding the complexities and costs associated with silicon-on-insulator substrates and reducing the risk of chip breakage.
Implementation Method 1
a high thermal conductivity region comprising a second silicon compound, the high thermal conductivity region having a bottom portion and a sidewall portion, wherein the second silicon compound has a thermal conductivity higher than silicon
Data Source
AI summary
An insulated gate bipolar transistor (IGBT) includes: a semiconductor substrate having a top surface and a bottom surface extending in horizontal directions; an isolation region comprising a first silicon compound; a high thermal conductivity region comprising a second silicon compound and having a bottom portion and a sidewall portion, wherein the second silicon compound has a thermal conductivity higher than silicon; a collector region of a first conductive type disposed on the isolation region; a buffer region of a second conductive type opposite to the first conductive type disposed on the collector region; a drift region of the second conductive type disposed on the buffer region; a body region of the first conductive type disposed in the drift region; and at least one source region of the second conductive type disposed in the body region. The isolation region encircles the high thermal conductivity region in the horizontal directions.