Bipolar Transistor Emitter Segmentation for Current Robustness
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Solution Overview
Problem
Conventional IGBT designs face a tradeoff between saturation voltage and switching losses, as well as switching losses and current robustness, limiting the ability to enhance current robustness without degrading other performance parameters.
Innovation Solution
A bipolar semiconductor device with a unique emitter region structure, comprising first and second type emitter regions of complementary doping types, and a recombination region, which allows for optimized doping concentrations and spatial arrangements to enhance current injection and carrier recombination, thereby improving current robustness while maintaining low switching losses and saturation voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the doping concentration in the emitter region is increased to improve current robustness, then the current robustness increases, but the saturation voltage increases and switching losses increase
Solution Approach 1:
The emitter region is segmented into multiple emitter regions with different doping concentrations. First emitter regions have a first doping concentration while second emitter regions have a second doping concentration that is lower than the first. This segmentation allows different parts of the emitter to serve different functions: high-doped regions provide current robustness while low-doped regions reduce switching losses and saturation voltage.
Solution Approach 2:
Different regions within the emitter are given different local properties through varying doping concentrations. The first emitter regions with higher doping concentration are positioned to provide current robustness where needed, while second emitter regions with lower doping concentration are positioned to reduce switching losses. This local differentiation resolves the contradiction by optimizing each region for its specific function.
2Reliability
If the doping concentration in the emitter region is increased to improve current robustness, then the current robustness increases, but the saturation voltage increases
Solution Approach 1:
The emitter region is divided into multiple emitter regions with different doping concentrations. First emitter regions with higher doping concentration provide current robustness, while second emitter regions with lower doping concentration maintain low saturation voltage. This segmentation allows the device to achieve both high current robustness and low saturation voltage simultaneously.
Solution Approach 2:
Different local doping concentrations are applied to different emitter regions. The first emitter regions have higher doping concentration optimized for current robustness, while second emitter regions have lower doping concentration optimized for low saturation voltage. This local quality differentiation resolves the contradiction between current robustness and saturation voltage.
3Ease of manufacture
If the emitter region structure is simplified to reduce device complexity, then the manufacturing process is easier, but the ability to optimize current robustness without degrading other parameters is reduced
Solution Approach 1:
The emitter region is segmented into first and second emitter regions with different doping concentrations, which can be formed using standard semiconductor fabrication processes like ion implantation or in-diffusion. This segmentation provides the complexity needed to optimize current robustness while remaining compatible with conventional manufacturing techniques.
Solution Approach 2:
The doping concentration parameter is varied across different emitter regions to optimize performance. First emitter regions have a first doping concentration and second emitter regions have a second doping concentration. This parameter change allows optimization of current robustness while maintaining compatibility with standard fabrication processes that can control doping concentrations.
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 proposed emitter region structure significantly increases the current robustness of IGBTs without degrading saturation voltage and switching losses, as demonstrated by increased destruction currents and reduced switching losses, enhancing the device's operational capabilities.
Implementation Method 1
a recombination region including recombination centers. The recombination region is located at least in the first type emitter regions and the third type emitter regions
Implementation Method 2
in a first implantation process, implanting dopant atoms of a first conductivity type into first surface sections of a first surface of a semiconductor body
Implementation Method 3
in a first activation process, activating at least a part of the dopant atoms implanted in the first implantation process to form first doped regions below the first surface sections
Data Source
AI summary
Disclosed is a bipolar semiconductor device, comprising a semiconductor body having a first surface; and a base region of a first doping type and a first emitter region in the semiconductor body, wherein the first emitter region adjoins the first surface and comprises a plurality of first type emitter regions of a second doping type complementary to the first doping type, a plurality of second type emitter regions of the second doping type, a plurality of third type emitter regions of the first doping type, and a recombination region comprising recombination centers, wherein the first type emitter regions and the second type emitter regions extend from the first surface into the semiconductor body, wherein the first type emitter regions have a higher doping concentration and extend deeper into the semiconductor body from the first surface than the second type emitter regions, wherein the third type emitter regions adjoin the first type emitter regions and the second type emitter regions, and wherein the recombination region is located at least in the first type emitter regions and the third type emitter regions.