Semiconductor Buffer Layer Segmentation for Short Circuit Capacity
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Solution Overview
Problem
Semiconductor apparatuses face challenges in maintaining short circuit capacity during load short circuit due to decreases in hole concentrations and increased electric field intensity in the boundary region between the n-type drift region and the first n-type buffer layer.
Innovation Solution
Incorporating a first p-type semiconductor region within the first n-type buffer layer, which suppresses decreases in hole concentrations and reduces electric field intensity by increasing hole injection and reducing space charge cancellation, thereby enhancing short circuit capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional single-layer n-type buffer layer is used, then the device structure is simple, but the short circuit capacity in load short circuit deteriorates due to decreases in hole concentrations and increased electric field intensity
Solution Approach 1:
The n-type buffer layer is divided into two distinct layers: a first n-type buffer layer with lower carrier concentration and greater thickness, and a second n-type buffer layer with higher carrier concentration and smaller thickness. This segmentation allows each layer to perform specific functions - the first layer maintains hole concentrations and the second layer manages electric field intensity - thereby improving short circuit capacity while maintaining reasonable structural complexity.
Solution Approach 2:
Different regions of the buffer layer structure are assigned different carrier concentrations and thicknesses to optimize local performance. The first n-type buffer layer has lower carrier concentration (1×10^16 to 1×10^18 cm^-3) and greater thickness (50-200 μm) to maintain hole concentrations, while the second n-type buffer layer has higher carrier concentration (1×10^18 to 1×10^20 cm^-3) and smaller thickness (10-50 μm) to control electric field intensity. This local differentiation resolves the contradiction between reliability and device complexity.
2Stability of the object's composition
If the n-type buffer layer thickness is increased to maintain hole concentrations, then hole concentration stability improves, but the electric field intensity in the boundary region increases
Solution Approach 1:
The buffer layer is segmented into two layers with different thicknesses and carrier concentrations. The first n-type buffer layer has greater thickness (50-200 μm) to maintain hole concentration stability, while the second n-type buffer layer has smaller thickness (10-50 μm) positioned at the boundary region to control electric field intensity. This segmentation resolves the contradiction by distributing different functions to different layers.
Solution Approach 2:
The first n-type buffer layer is designed with lower carrier concentration and greater thickness to provide stable hole concentrations throughout the bulk, while the second n-type buffer layer is designed with higher carrier concentration and smaller thickness specifically at the boundary region where electric field intensity needs to be controlled. This local quality differentiation allows simultaneous optimization of both hole concentration stability and electric field management.
3Stress or pressure
If the carrier concentration in the n-type buffer layer is increased to reduce electric field intensity, then electric field control improves, but hole concentrations in the drift region decrease
Solution Approach 1:
The buffer layer is divided into two segments with different carrier concentrations. The first n-type buffer layer has lower carrier concentration (1×10^16 to 1×10^18 cm^-3) to maintain adequate hole concentrations, while the second n-type buffer layer has higher carrier concentration (1×10^18 to 1×10^20 cm^-3) to control electric field intensity. This segmentation resolves the contradiction by allowing each layer to optimize for its specific function without compromising the other.
Solution Approach 2:
The first n-type buffer layer maintains lower carrier concentration to preserve hole concentrations in the drift region, while the second n-type buffer layer is positioned at the boundary region with higher carrier concentration to locally control electric field intensity. This local quality approach allows high carrier concentration only where needed for electric field control, preventing excessive reduction of hole concentrations in the drift region.
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 improves short circuit capacity by maintaining higher hole concentrations and reducing electric field intensity in the boundary region, leading to increased reliability and performance in load short circuit conditions.
Implementation Method 1
the first p-type semiconductor region suppresses decreases in the hole concentrations in the n-type drift region and the first n-type buffer layer
Implementation Method 2
reduces the electric field intensity in a boundary region between the n-type drift region and the first n-type buffer layer
Data Source
AI summary
A semiconductor apparatus includes a semiconductor substrate including a semiconductor device. The semiconductor device includes a first n-type buffer layer, a second n-type buffer layer, and a first p-type semiconductor region. A first maximum peak concentration of first n-type carriers contained in the first n-type buffer layer is smaller than a second maximum peak concentration of second n-type carriers contained in the second n-type buffer layer. The first p-type semiconductor region is formed in the first n-type buffer layer. The first p-type semiconductor region has a narrower width than the first n-type buffer layer.