IGBT Termination Trenches for Reduced Area and Faster Switching

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Solution Overview

Problem

The semiconductor industry faces high manufacturing costs and slow switching speeds in reverse blocking insulated gate bipolar transistors (IGBTs) due to the large area required for the diffused junction termination region, which increases die size and minority carrier densities.

Innovation Solution

The formation of a semiconductor device with a reduced termination region area by using a plurality of termination trenches surrounding the active region, which reduces the manufacturing cost and time, and enhances switching speed by minimizing minority carrier injection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a large area is used for the diffused junction termination region, then the reverse voltage capability is improved, but the die size and manufacturing cost increase

Engineering Contradiction:

Improvereverse voltage capabilityVSAvoidtermination region area

Core Design Contradiction:

ReliabilityVSArea of stationary object

Solution Approach 1:

The termination region is segmented into multiple discrete termination regions arranged in a pattern around the active region, rather than using a continuous large-area termination region. This segmentation allows the device to achieve adequate reverse voltage capability with a reduced overall termination area, directly resolving the contradiction between reverse voltage capability and termination region area.

Inventive Principle:

Principle #1Segmentation

2Reliability

If a large area is used for the diffused junction termination region, then the reverse voltage capability is improved, but the manufacturing cost increases

Engineering Contradiction:

Improvereverse voltage capabilityVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

By segmenting the termination region into multiple smaller discrete regions, the patent reduces the total area required for termination, which directly reduces manufacturing cost while maintaining adequate reverse voltage capability through the distributed arrangement of termination regions.

Inventive Principle:

Principle #1Segmentation

3Reliability

If high minority carrier densities are present in the termination region, then the reverse voltage capability is improved, but the switching speed decreases

Engineering Contradiction:

Improvereverse voltage capabilityVSAvoidswitching speed

Core Design Contradiction:

ReliabilityVSSpeed

Solution Approach 1:

Segmenting the termination region reduces the total volume where minority carriers can accumulate, thereby reducing minority carrier densities overall. This enables faster switching speeds while maintaining reverse voltage capability through the distributed termination structure that provides adequate voltage blocking across multiple regions.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies different properties to different regions: the active region maintains high minority carrier densities for optimal forward conduction, while the segmented termination regions use lower minority carrier densities for faster switching. This local differentiation resolves the contradiction between reverse voltage capability and switching speed.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS9553165B2Method of forming a semiconductor device

Publication Date: 2017.01.24 SEMICON COMPONENTS IND LLC

AI summary

In one embodiment, an IGBT is formed to include a plurality of termination trenches in a termination region of the IGBT. An embodiment may include that one end of one or more termination trenches may be exposed on one surface of the semiconductor device.