Power Semiconductor Mesa Cells With Insulated Control Electrodes

Solution Overview

Problem

Power semiconductor devices face significant challenges in minimizing losses due to uncontrolled transitions between blocking and conducting states, which can lead to damage and inefficiencies in applications like power converters and electric motors.

Innovation Solution

The design incorporates a power semiconductor device with first and second cells, each having a mesa structure with a channel region and a guidance electrode, where the control electrode is insulated from the load terminal structure, allowing for precise control of current flow and minimizing uncontrolled transitions by spatially confining the mesas within an insulation structure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a power semiconductor device uses conventional control electrode structures without insulation, then the device can conduct load current, but uncontrolled transitions between blocking and conducting states occur causing significant damages and losses

Engineering Contradiction:

Improvedevice reliabilityVSAvoidswitching losses

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The device is divided into multiple independent cells (first cell, second cell, etc.), each with its own mesa structure containing a control electrode. This segmentation allows independent control of each cell, preventing uncontrolled transitions and reducing switching losses by enabling precise control of current flow paths.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

An insulation structure is introduced as an intermediary element between the control electrode and the surrounding environment. This insulation structure prevents unwanted electrical interactions and uncontrolled transitions, thereby improving device reliability and reducing switching losses by maintaining proper electrical isolation.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If the control electrode is not insulated from the load terminal structure, then the device structure is simpler, but uncontrolled state transitions occur leading to device damage

Engineering Contradiction:

Improvedevice reliabilityVSAvoiddevice structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The device is divided into multiple independent cells (first cell, second cell, etc.), each with its own mesa structure containing a control electrode. This segmentation allows independent control of each cell, preventing uncontrolled transitions and reducing switching losses by enabling precise control of current flow paths.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

An insulation structure is introduced as an intermediary element between the control electrode and the surrounding environment. This insulation structure prevents unwanted electrical interactions and uncontrolled transitions, thereby improving device reliability and reducing switching losses by maintaining proper electrical isolation.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Loss of energy

If mesa structures have larger extension dimensions, then manufacturing is easier, but uncontrolled transitions between blocking and conducting states increase causing energy losses

Engineering Contradiction:

Improveswitching lossesVSAvoidmesa structure precision

Core Design Contradiction:

Loss of energyVSManufacturing precision

Solution Approach 1:

The total extension of each mesa structure in the direction perpendicular to load current is reduced to less than 100 nm. This parameter change in mesa dimensions improves control over current flow and reduces uncontrolled transitions, thereby reducing switching losses while maintaining manufacturability through precise nanoscale fabrication.

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

This configuration reduces switching losses and enhances the reliability of power semiconductor devices by preventing uncontrolled changes between states, thereby improving efficiency and extending the lifespan of the devices.

Implementation Method 1

the control electrode may be provided with a control signal having a voltage within a first range so as to induce a load current path within the channel region

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 2

a control electrode structure for controlling the load current within the first mesa and the second mesa, the control electrode structure being electrically insulated from the first load terminal structure

Methodology Applied

Scientific EffectElectrical insulation: Dielectric

Implementation Method 3

a guidance electrode electrically insulated from the control electrode structure and arranged in between the first mesa and the second mesa

Methodology Applied

Scientific EffectElectrical insulation: Dielectric

Data Source

PatentUS10453918B2Power semiconductor device having cells with channel regions of different conductivity types

Publication Date: 2019.10.22 INFINEON TECHNOLOGIES AG

AI summary

A power semiconductor device includes a semiconductor body coupled to first and second load terminal structures, first and second cells electrically connected to the first load terminal structure and to a drift region, the drift region having a first conductivity type; a first mesa in the first cell and including: a port region electrically connected to the first load terminal structure, and a channel region coupled to the drift region; a second mesa in the second cell and including: a port region of the opposite conductivity type and electrically connected to the first load terminal structure, and a channel region coupled to the drift region. Each mesa is spatially confined, in a direction perpendicular to a direction of the load current within the respective mesa, by an insulation structure. The insulation structure houses a control electrode structure, and a guidance electrode arranged between the mesas.