Super-Junction IGBT Structure for Lower On-State Voltage Drop

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Solution Overview

Problem

Existing IGBT devices face challenges in achieving a balance between low on-state voltage drop and high current density, which affects the efficiency and performance of power electronic systems.

Innovation Solution

The IGBT device incorporates a super junction structure with an N-type carrier injection layer, which increases the potential of the P-type body region, blocking holes injected from the collector and enhancing hole concentration, thereby reducing the on-state voltage drop.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If conventional IGBT structure is used, then manufacturing process is simple, but on-state voltage drop is high and current density is limited

Engineering Contradiction:

Improveon-state voltage dropVSAvoiddevice structure

Core Design Contradiction:

Loss of energyVSDevice complexity

Solution Approach 1:

The drift region is segmented into multiple N-type epitaxial layers separated by P-type body regions, creating a multi-layered cell structure. This segmentation allows for optimized carrier injection paths and reduced on-state voltage drop while maintaining manageable device complexity through modular architecture.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent implements a nested structure where N-type carrier injection layers are embedded within the N-type epitaxial layers, and P-type body regions are positioned between them. This nested arrangement enables efficient carrier injection while maintaining a compact device structure that does not excessively increase complexity.

Inventive Principle:

Principle #7Nested doll (Nesting)

2Productivity

If higher current density is pursued, then power conversion efficiency improves, but on-state voltage drop increases

Engineering Contradiction:

Improvecurrent densityVSAvoidon-state voltage drop

Core Design Contradiction:

ProductivityVSLoss of energy

Solution Approach 1:

N-type carrier injection layers are introduced into the drift region before the main conduction path is established. These pre-positioned injection layers proactively supply carriers to reduce on-state voltage drop, enabling the device to achieve higher current density without the penalty of increased voltage drop.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent modifies the electrical parameters of the drift region by introducing N-type carrier injection layers with specific doping concentrations and depths. This changes the carrier concentration profile in the drift region, enabling simultaneous achievement of high current density and low on-state voltage drop through optimized parameter distribution.

Inventive Principle:

Principle #35Parameter changes

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

The introduction of the N-type carrier injection layer improves the figure of merit (FOM) of the IGBT device by 15% compared to existing MPT-type IGBTs and 5% compared to existing super-junction-based IGBTs, leading to enhanced performance and efficiency.

Implementation Method 1

the potential of a region corresponding to the P-type body region is increased, achieving a blocking effect on holes injected from a collector

Methodology Applied

Scientific EffectPotential barrier blocking: Electric Field

Implementation Method 2

the holes gather near the N-type carrier injection layer. By increasing the hole concentration, the on-state voltage drop of the IGBT device is reduced

Methodology Applied

Scientific EffectCharge carrier concentration:

Implementation Method 3

implanting N-type dopant ions into the N-type epitaxial layer by means of an ion implantation process, so as to form the N-type carrier injection layer

Methodology Applied

Scientific EffectIon implantation: Ion Implantation

Data Source

PatentUS12310069B2IGBT device and method of making the same

Publication Date: 2025.05.20 SHANGHAI HUAHONG GRACE SEMICON MFG CORP

AI summary

An IGBT device and a method for manufacturing it, the device includes a super junction structure that has several N-type pillars and P-type pillars arranged alternately; a cell unit that is located in an N-type epitaxial layer, and the N-type epitaxial layer is located above the N-type substrate; each cell unit includes a trench gate, a P-type body region, and a source region; an N-type carrier injection layer, the N-type carrier injection layer is located in the N-type epitaxial layer, and the N-type carrier injection layer is spaced apart from the N-type substrate by the N-type epitaxial layer; the bottom of the P-type body region is located in the N-type carrier injection layer; and a collector region that is located at the bottom of the N-type substrate.