IGBT Gate Electrode Segmentation for Low ON-Voltage
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Solution Overview
Problem
Existing semiconductor devices with insulated gate bipolar transistors (IGBTs) face challenges in achieving optimal turn-on characteristics and ON-voltage due to the absence of channels in second gate trenches not in contact with emitter regions, leading to higher ON-voltage and fewer current paths during turn-on.
Innovation Solution
A semiconductor device design featuring first and second gate electrodes with resistive sections of different resistances, where the second gate electrodes are connected to the gate electrode pad, allowing for controlled voltage application and channel creation in both first and second gate trenches, enhancing turn-on characteristics and reducing ON-voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If second gate trenches are not in contact with emitter regions, then turn-on characteristics are improved through hole accumulation, but ON-voltage increases and current paths decrease
Solution Approach 1:
The gate electrode is segmented into two distinct types: first gate electrodes contacting emitter regions for current conduction, and second gate electrodes not contacting emitter regions for hole accumulation. This segmentation allows each type to fulfill its specific function independently, resolving the contradiction between improving turn-on characteristics and maintaining low ON-voltage.
Solution Approach 2:
Different regions of the gate structure are given different properties: first gate electrodes have direct contact with emitter regions to provide low-resistance current paths, while second gate electrodes are positioned to accumulate holes without direct contact. This local differentiation optimizes both turn-on characteristics and ON-voltage simultaneously.
2Productivity
If second gate trenches are not in contact with emitter regions, then electron injection is enhanced, but number of current paths decreases
Solution Approach 1:
The gate structure is divided into first gate electrodes that provide current paths and second gate electrodes that enhance electron injection through hole accumulation. This segmentation allows the system to achieve both high electron injection efficiency and sufficient current paths by distributing functions across different electrode types.
Solution Approach 2:
The gate electrode structure serves multiple functions through its segmented design: first gate electrodes provide current conduction paths, while second gate electrodes provide hole accumulation for electron injection enhancement. This multi-functionality resolves the contradiction between improving electron injection and maintaining adequate current paths.
3Ease of operation
If resistive sections with different resistances are used, then voltage control is improved, but device complexity increases
Solution Approach 1:
Different resistive sections are assigned to different gate electrode groups: first resistive sections with first resistance values control first gate electrodes, while second resistive sections with second resistance values control second gate electrodes. This local differentiation enables independent voltage control optimization for each electrode type, improving overall voltage control despite increased structural complexity.
Solution Approach 2:
The resistive control network is segmented into first and second resistive sections with different resistance values, each tailored to control specific gate electrode types. This segmentation allows optimized voltage control characteristics for turn-on and turn-off operations, managing the trade-off between control precision and device complexity.
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 design achieves favorable turn-on characteristics and reduced ON-voltage by ensuring current paths through both types of gate trenches, improving the control and efficiency of the semiconductor device's operation.
Implementation Method 1
a first resistive section having a first resistance and being electrically connected to the first gate electrode, a second resistive section having a second resistance greater than the first resistance and electrically connected to the second gate electrode
Data Source
AI summary
A semiconductor device includes a collector layer of a first conductive type, a drift layer of a second conductive type, an accumulation region of the second conductive type, a base region of the first conductive type, emitter regions of the second conductive type, a first gate electrode in contact with the emitter regions via first gate insulating film, a second gate electrode facing the first gate electrode via the base region, and being in contact with the emitter regions via second gate insulating film, a first resistive section electrically connected to the first gate electrode, a second resistive section having a larger resistance than does the first resistive section, and electrically connected to the second gate electrode, and a gate electrode pad electrically connected to the first and second resistive sections.