AlGaN Field Plate Electrode Segmentation for Electric Field Relaxation
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Solution Overview
Problem
Semiconductor devices with nitride or wide bandgap materials face reliability issues due to electric field concentration, leading to crystal defects and fluctuations in properties, especially when subjected to high voltages, and existing field plate structures can introduce film thickness variations and stress, causing further reliability concerns.
Innovation Solution
A semiconductor device design featuring non-doped AlXGa1-XN and AlYGa1-YN layers with field plate electrodes whose lengths change periodically in a specific direction, reducing electric field peaks by dispersing concentration across multiple end portions, thereby improving reliability and reducing fluctuations in breakdown voltage and turn on-resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a field plate structure is used to relax electric field concentration, then reliability is improved, but manufacturing complexity increases due to multiple depositing steps
Solution Approach 1:
The field plate electrode is divided into multiple segments with different lengths in the second direction, creating multiple electric field relaxation zones. This segmentation allows the electric field to be distributed across several regions rather than concentrated at a single point, effectively reducing peak electric field intensity while maintaining a manageable manufacturing process
Solution Approach 2:
Different portions of the field plate electrode structure have different lengths in the second direction, creating local variations in electric field distribution. This local quality variation allows targeted relaxation of electric field concentration at specific locations without requiring complex multi-layer insulating structures
2Reliability
If insulating film thickness is increased to reduce electric field concentration, then reliability is improved, but film stress increases causing cracks
Solution Approach 1:
The field plate electrode is segmented with varying lengths in the second direction, creating multiple discrete relaxation zones. This segmentation achieves electric field distribution without requiring increased insulating film thickness, thereby avoiding the film stress and cracking issues that would result from thicker insulating layers
3Reliability
If multiple insulating films are deposited to create field plate structure, then electric field relaxation is achieved, but property fluctuations increase due to film thickness variations
Solution Approach 1:
The field plate electrode is divided into multiple segments with different lengths in the second direction, creating a stepped configuration. This segmentation achieves effective electric field relaxation through geometric variation rather than through multiple insulating film layers, thereby eliminating the manufacturing precision issues associated with controlling film thickness across multiple deposition steps
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 periodic change in field plate electrode lengths effectively disperses electric field concentration, reducing the likelihood of crystal defects and improving the reliability of semiconductor devices by stabilizing properties such as leakage current, breakdown voltage, and turn on-resistance.
Implementation Method 1
The HFET can be of low turn on-resistances because of a high mobility in hetero-structure interface channels and a high electron density due to piezoelectric polarization.
Data Source
AI summary
A semiconductor device includes: a first semiconductor layer of non-doped AlXGa1-XN (0≦X<1); a second semiconductor layer of non-doped or n-type AlYGa1-YN (0<Y≦1, X<Y) on the first semiconductor layer; a first electrode on the second semiconductor layer; a second electrode on the second semiconductor layer that is separated from the first electrode and electrically connected to the second semiconductor layer; a first insulating film covering the first and second electrodes; a first field plate electrode electrically connected to the first electrode and covered by a second insulating film; and a second field plate electrode on the second insulating film, wherein a length of at least one of the first and second field plate electrodes in a first direction from the first electrode toward the second electrode changes periodically in a second direction intersecting the first direction.