IE-Type Trench IGBT Segmented Cell Design
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Solution Overview
Problem
IE-type trench IGBTs face a reduction in breakdown voltage when attempting to widen inactive cells for further conductivity modulation, as there is no emitter contact in the inactive cell, leading to reduced reliability and performance.
Innovation Solution
The design incorporates linear unit cell areas with a narrower active cell area and a wider inactive cell area, featuring a floating P-type region deeper than the trenches, which enhances IE effects without reducing breakdown voltage, and includes a manufacturing process that forms a P-type floating region and N-type hole barrier region to prevent direct hole discharge and increase electron injection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the width of inactive cell is increased to promote conductivity modulation, then conductivity modulation is improved, but breakdown voltage is reduced
Solution Approach 1:
The cell area is segmented into active cell areas and inactive cell areas with different width ratios. The inactive cell area is divided into a first inactive cell area and a second inactive cell area, allowing different regions to serve different functions. This segmentation enables the inactive cells to contribute to conductivity modulation while maintaining adequate breakdown voltage through the structured division of functional zones.
Solution Approach 2:
Different regions of the device are assigned different local properties: active cell areas have emitter contacts for carrier injection, while inactive cell areas have floating P-type regions for hole accumulation. The first and second inactive cell areas have different width ratios relative to their corresponding active cell areas, creating local quality variations that optimize both conductivity modulation and breakdown voltage in different zones.
2Device complexity
If inactive cells are widened without emitter contact, then device simplification is achieved, but breakdown voltage is rapidly reduced
Solution Approach 1:
The inactive cell area is segmented into first and second inactive cell areas with different width ratios. This segmentation allows the device to maintain structural simplicity while preventing breakdown voltage reduction by creating distinct functional zones within the inactive regions that collectively support both simplification and voltage maintenance.
Solution Approach 2:
The width ratio between inactive cell area and active cell area is optimized at different locations. The first inactive cell area has a first width ratio and the second inactive cell area has a second width ratio, allowing parameter variation to maintain breakdown voltage while achieving device simplification through the inactive cell configuration.
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 configuration effectively enhances conductivity modulation while maintaining high breakdown voltage, thereby improving the reliability and performance of the IE-type trench IGBT.
Implementation Method 1
an IE-type trench IGBT using IE (Injection Enhancement) effects has been developed to further promote conductivity modulation
Implementation Method 2
includes a manufacturing process that forms a P-type floating region and N-type hole barrier region to prevent direct hole discharge and increase electron injection
Data Source
AI summary
The invention of the present application provides an IE-type trench IGBT. In the IE-type trench IGBT, each of linear unit cell areas that configure a cell area is comprised principally of linear active and inactive cell areas. The linear active cell area is divided into an active section having an emitter region and an inactive section as seen in its longitudinal direction.