IE Type Trench Gate IGBT Cell Segmentation for Switching Speed

Solution Overview

Problem

Narrow active cell IE type trench gate IGBTs face a reduction in switching speed due to increased gate capacity when cells are shrunk to enhance IE effects.

Innovation Solution

The cell formation area of the IE type trench gate IGBT is composed of first and second linear unit cell areas with linear active and hole collector cell areas, and linear inactive cell areas disposed between them, which helps in preventing the reduction of switching speed.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If cells are shrunk to enhance IE effects, then IE effects are enhanced, but switching speed is reduced due to increased gate capacity

Engineering Contradiction:

ImproveIE effectsVSAvoidswitching speed

Core Design Contradiction:

ReliabilityVSSpeed

Solution Approach 1:

The cell formation area is divided into multiple linear unit cell areas, each containing active cell areas, hole collector areas, and inactive cell areas. This segmentation allows the active cell width to be narrowed for enhanced IE effects while the overall structure maintains optimized electrical characteristics through the distributed arrangement of multiple cell types.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions within the cell formation area are assigned different functions and dimensions. The active cell areas have narrowed widths to enhance IE effects locally, while inactive cell areas provide spacing and the hole collector areas collect carriers. This local differentiation allows each region to optimize its function without compromising overall switching speed.

Inventive Principle:

Principle #3Local quality

2Reliability

If active cell width is narrowed to enhance IE effects, then IE effects are enhanced, but gate capacity increases reducing switching speed

Engineering Contradiction:

ImproveIE effectsVSAvoidgate capacity

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The cell formation area is divided into multiple linear unit cell areas, each containing active cell areas, hole collector areas, and inactive cell areas. This segmentation allows the active cell width to be narrowed for enhanced IE effects while the overall structure maintains optimized electrical characteristics through the distributed arrangement of multiple cell types.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Inactive cell areas are introduced as intermediary regions between active cell areas and hole collector areas. These inactive regions provide electrical isolation and allow the active cells to be narrowed for enhanced IE effects without directly increasing the total gate capacity, as the inactive areas do not contribute to the active gate capacitance.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Speed

If linear unit cell areas are disposed between active and inactive cell areas, then switching speed is maintained, but device structure becomes more complex

Engineering Contradiction:

Improveswitching speedVSAvoidcell formation area structure

Core Design Contradiction:

SpeedVSDevice complexity

Solution Approach 1:

The cell formation area is divided into multiple linear unit cell areas, each containing active cell areas, hole collector areas, and inactive cell areas. This segmentation allows the active cell width to be narrowed for enhanced IE effects while the overall structure maintains optimized electrical characteristics through the distributed arrangement of multiple cell types.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Multiple functional elements (active cells, hole collectors, and inactive cells) are merged into a single repeating linear unit cell structure. This modular design, where each linear unit cell area contains all necessary components in a standardized arrangement, simplifies the overall device structure despite the presence of multiple cell types, as the repeating pattern can be manufactured using standard semiconductor fabrication processes.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS10304951B2IE type trench gate IGBT

Publication Date: 2019.05.28 RENESAS ELECTRONICS CORP

AI summary

In a method of further enhancing the performance of a narrow active cell IE type trench gate IGBT having the width of active cells narrower than that of inactive cells, it is effective to shrink the cells so that the IE effects are enhanced. However, when the cells are shrunk simply, the switching speed is reduced due to increased gate capacitance. A cell formation area of the IE type trench gate IGBT is basically composed of first linear unit cell areas having linear active cell areas, second linear unit cell areas having linear hole collector areas and linear inactive cell areas disposed therebetween.