Monolithic IGBT Diode Integration for Quasi-Resonant Converters

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Solution Overview

Problem

Conventional quasi-resonant converters require co-packaging of separate IGBT and diode dies, increasing manufacturing costs and resistance, and often necessitate complex backside processing, which can lead to snapback issues and wafer damage.

Innovation Solution

A monolithic IGBT structure integrated with a lateral diode, formed using the channel stop region, eliminating the need for co-packaging and backside processing, allowing for a larger IGBT die and smaller package size without snapback problems, and enabling separate control of injection efficiency without conventional lifetime control processes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If separate IGBT and diode dies are co-packaged, then the device can achieve required functionality, but manufacturing cost increases and resistance increases

Engineering Contradiction:

Improvedevice functionalityVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent merges the IGBT and diode functions into a single monolithic semiconductor structure. The IGBT device includes an integrated body diode formed within the same semiconductor substrate, eliminating the need for separate diode die and co-packaging operations. This integration reduces manufacturing complexity and cost while maintaining the required reverse conduction functionality.

Inventive Principle:

Principle #5Merging (Combining)

2Reliability

If separate IGBT and diode dies are co-packaged, then the device can achieve required functionality, but the IGBT must be made smaller which increases resistance and reduces current handling capability

Engineering Contradiction:

Improvedevice functionalityVSAvoidpackage footprint

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines both the IGBT and diode functions within a single semiconductor die, eliminating the need for separate diode die and reducing the overall package footprint. This integration allows the IGBT to be optimized for current handling capability without being constrained by the need to accommodate separate components.

Inventive Principle:

Principle #5Merging (Combining)

3Reliability

If backside processing is used to form reverse conducting diode, then the diode can be integrated, but production cost increases and wafer damage risk increases

Engineering Contradiction:

Improvediode integrationVSAvoidproduction cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

Instead of forming the diode through backside processing as in conventional approaches, the patent forms the body diode through frontside processing during the standard IGBT fabrication sequence. The diode is created using the channel stop region and existing doped layers, eliminating the need for additional backside implantation steps and associated costs.

Inventive Principle:

Principle #13The other way round (Inversion)

4Reliability

If backside processing is used to form reverse conducting diode, then the diode can be integrated, but snapback issues occur during device turn-on

Engineering Contradiction:

Improvediode integrationVSAvoidsnapback

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent inverts the conventional approach by forming the diode through frontside processing rather than backside processing. This alternative formation method using the channel stop region and existing doped layers eliminates the snapback phenomenon that occurs during device turn-on in conventionally processed devices.

Inventive Principle:

Principle #13The other way round (Inversion)

Data Source

PatentUS9093286B2Monolithic IGBT and diode structure for quai-resonant converters

Publication Date: 2015.07.28 ALPHA & OMEGA SEMICONDUCTOR INC

AI summary

This invention discloses a semiconductor power device formed in a semiconductor substrate. The semiconductor power device further includes a channel stop region near a peripheral of the semiconductor substrate wherein the channel stop region further includes a peripheral terminal of a diode corresponding with another terminal of the diode laterally opposite from the peripheral terminal disposed on an active area of the semiconductor power device. In an embodiment of this invention, the semiconductor power device is an insulated gate bipolar transistor (IGBT).