GaN Seal Ring Trench Structure for Moisture Barrier Reliability

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Solution Overview

Problem

GaN devices, used in high electron mobility transistors, are susceptible to moisture penetration, which can affect their performance and integrity, limiting their further improvement in power applications.

Innovation Solution

A semiconductor structure with a trench in the channel layer lined with a moisture barrier layer to prevent moisture ingress, combined with metal material within the trench and extending outside the trench, providing a seal ring structure that integrates with the GaN layer to enhance device reliability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If GaN devices are used to achieve high electron mobility and improved performance, then on-resistance and breakdown voltage are improved, but susceptibility to moisture penetration increases

Engineering Contradiction:
Improvedevice performanceVSAvoidmoisture penetration
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The device structure is segmented by introducing a trench that divides the semiconductor layer into distinct regions. This trench, lined with moisture barrier material, creates a physical segmentation that isolates the active region from moisture ingress pathways, thereby protecting the high-performance GaN structure while maintaining its performance benefits.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A moisture barrier layer is introduced as an intermediary substance between the external environment and the GaN device. This barrier layer, deposited within the trench structure, acts as a mediator that blocks moisture penetration while allowing the device to maintain its high electron mobility and performance characteristics.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If a trench structure is introduced to prevent moisture ingress, then moisture barrier effectiveness is improved, but device complexity increases

Engineering Contradiction:
Improvemoisture ingressVSAvoidstructure complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

Instead of creating complex three-dimensional protective structures, the invention uses thin film deposition techniques to line the trench walls with moisture barrier material. This approach provides effective moisture protection through thin conformal films that follow the trench geometry, avoiding the need for complex structural modifications while achieving the desired barrier effect.

Inventive Principle:
Principle #30Flexible shells and thin films

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 seal ring structure effectively prevents moisture ingress into the active region of GaN devices, enhancing their performance and reliability by creating a barrier against environmental moisture, thus overcoming the susceptibility of GaN devices to moisture-related degradation.

Implementation Method 1

a moisture barrier layer lining sidewalls and a bottom surface of the trench

Methodology Applied
Scientific EffectMoisture barrier: Adsorption

Data Source

PatentEP4401124A1Seal ring structures
Publication Date: 2024.07.17 GLOBALFOUNDRIES US INC
  • EP4401124A1 patent drawingFigure 1
  • EP4401124A1 patent drawingFigure 2
  • EP4401124A1 patent drawingFigure 3

AI summary

The present disclosure relates to semiconductor structures and, more particularly, to seal ring structures and methods of manufacture. The structure includes: a semiconductor substrate; a channel layer above the semiconductor substrate; a trench within the channel layer, extending to the semiconductor substrate; and a moisture barrier layer lining sidewalls and a bottom surface of the trench.