Segmented RC IGBT Layout for Reverse Current and Loss Control

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Solution Overview

Problem

Existing power semiconductor devices, such as separate IGBTs and diodes, face challenges in controlling reverse load currents efficiently, leading to increased on-state losses and thermal issues, particularly in high voltage and high current applications.

Innovation Solution

A single-chip RC IGBT design is implemented, where the active region is separated into IGBT-only and RC IGBT regions, each controlled by distinct signals to manage forward and reverse load currents independently, optimizing the conduction of both currents and reducing thermal behavior complexities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If separate IGBT and diode are used, then device complexity is reduced, but on-state losses increase and thermal behavior becomes more complex

Engineering Contradiction:

Improveon-state lossesVSAvoiddevice complexity

Core Design Contradiction:

Loss of energyVSDevice complexity

Solution Approach 1:

The patent combines separate IGBT and diode functions into a single integrated RC IGBT device structure, where the IGBT and reverse conductive path share a common device architecture, reducing the number of discrete components and improving thermal coupling between the two functions

Inventive Principle:

Principle #5Merging (Combining)

2Ease of operation

If RC IGBT region conducts both forward and reverse currents, then control capability is improved, but device complexity increases

Engineering Contradiction:

Improvecontrol capabilityVSAvoiddevice complexity

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The active region is segmented into distinct IGBT-only region and RC IGBT region, with each region having specific doping profiles and structural characteristics optimized for its function, allowing independent control and optimization of forward and reverse current conduction paths

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the active region are given different local properties: the IGBT-only region has doping profiles optimized for forward conduction, while the RC IGBT region has additional doping structures enabling both forward and reverse conduction, allowing each region to perform its specific function with optimal characteristics

Inventive Principle:

Principle #3Local quality

3Ease of operation

If active region is separated into multiple regions, then control over forward and reverse currents is improved, but manufacturing precision requirements increase

Engineering Contradiction:

Improvecontrol over forward and reverse currentsVSAvoidmanufacturing precision

Core Design Contradiction:

Ease of operationVSManufacturing precision

Solution Approach 1:

The active region is divided into IGBT-only and RC IGBT regions with clearly defined spatial boundaries and doping profiles, where each region can be independently optimized and controlled, allowing precise management of forward and reverse current characteristics through regional doping variations

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS20250006825A1RC IGBT and Method of Operating a Half Bridge Circuit

Publication Date: 2025.01.02 INFINEON TECHNOLOGIES AG

AI summary

An RC IGBT includes, in a single chip, an active region configured to conduct both a forward load current and a reverse load current between a first load terminal at a front side of a semiconductor body of the RC IGBT and a second load terminal at a back side of the semiconductor body. The active region is separated into at least an IGBT-only region and an RC IGBT region. At least 90% of the IGBT-only region is configured to conduct, based on a first control signal, only the forward load current. At least 90% of the RC IGBT region is configured to conduct the reverse load current and, based on a second control signal, the forward load current.