Hydrogen Occlusion in Semiconductor Edge Termination

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Solution Overview

Problem

Hydrogen penetration into semiconductor devices, particularly from moisture and aluminum source electrodes, affects the characteristics of insulating films, leading to shifts in gate voltage thresholds and issues in edge termination structures.

Innovation Solution

A semiconductor device design incorporating titanium films as protective layers in both the edge termination and active regions to occlude hydrogen, preventing its penetration and maintaining the integrity of insulating films, with specific thickness and placement strategies to ensure effective hydrogen occlusion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If aluminum is used as a source electrode, then electrical contact is improved, but hydrogen enters the semiconductor device causing gate voltage threshold shifts

Engineering Contradiction:

Improveelectrical contactVSAvoidhydrogen penetration

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

A barrier metal layer (titanium, tungsten, or tungsten silicide) is introduced as an intermediary between the aluminum source electrode and the semiconductor device. This barrier layer prevents hydrogen from the aluminum from penetrating into the semiconductor device, while still maintaining good electrical contact properties.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The source electrode structure is made composite by combining aluminum with a barrier metal layer. This composite structure leverages the excellent electrical conductivity of aluminum while the barrier metal component prevents hydrogen penetration, solving both electrical contact and hydrogen occlusion requirements.

Inventive Principle:

Principle #40Composite materials

2Ease of operation

If moisture is present on the front surface, then device operation continues, but hydrogen from moisture enters the semiconductor device affecting insulating film characteristics

Engineering Contradiction:

Improvedevice operationVSAvoidhydrogen penetration from moisture

Core Design Contradiction:

Ease of operationVSObject-generated harmful factors

Solution Approach 1:

A protective film (nitride film or oxide nitride film) is formed on the front surface of the semiconductor device before operation. This preliminary protective layer prevents hydrogen from moisture in the environment from entering the device during normal operation, while not affecting device functionality.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The protective film creates an inert barrier environment on the front surface, preventing interaction between moisture-containing atmosphere and the semiconductor device interior, thus blocking hydrogen penetration pathways.

Inventive Principle:

Principle #39Inert atmosphere (Inert environment)

3Device complexity

If no protective film is provided in the edge termination structure section, then device structure is simple, but hydrogen penetration occurs causing breakdown voltage variations

Engineering Contradiction:

Improvestructure simplicityVSAvoidbreakdown voltage stability

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

A protective film is selectively formed only in the edge termination structure section where hydrogen penetration and breakdown voltage issues occur. This localized approach provides protection where needed while maintaining simplicity in other device regions.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The protective film structure is segmented into different regions: a first protective film in the edge termination structure section and a second protective film in the active region. This segmentation allows optimized protection strategies for different functional areas of the device.

Inventive Principle:

Principle #1Segmentation

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 use of titanium films effectively reduces hydrogen penetration, stabilizing gate threshold voltages and preventing breakdown voltage variations in edge termination structures, enhancing the reliability of semiconductor devices.

Implementation Method 1

The first protective film may occlude hydrogen

Methodology Applied

Scientific EffectHydrogen occlusion: Absorption (physical)

Data Source

PatentUS10090379B2Hydrogen occlusion semiconductor device

Publication Date: 2018.10.02 FUJI ELECTRIC CO LTD

AI summary

When hydrogen penetrates in to the semiconductor device, a gate voltage threshold of a gate structure (Vth) is shifted. Penetrating of hydrogen into the semiconductor device from the edge termination structure section which is positioned at an end portion of the semiconductor device is prevented. To provide a semiconductor device comprising a semiconductor substrate in which an active region and an edge termination structure section which is provided around the active region are provided, a first lower insulating film which is provided in the edge termination structure section on the semiconductor substrate, and a first protective film which is provided on the first lower insulating film, and is electrically insulated from the semiconductor substrate, and occludes hydrogen.