Boundary Trench Gate for Semiconductor Avalanche Resistance
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Solution Overview
Problem
Conventional semiconductor devices with RC-IGBTs experience insulation film deterioration due to electric field concentration at the end portions of trench gates with different spacings, leading to reduced avalanche breakdown resistance.
Innovation Solution
The semiconductor device incorporates a boundary trench gate connected to the end portions of first and second trench gates with different spacings, which intersects the direction of the trench gates, effectively reducing electric field concentration and preventing insulation film deterioration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If first trench gates and second trench gates with different spacings are disposed adjacent to each other in the direction of extension of the trench gates, then avalanche breakdown resistance is ensured, but electric field concentration occurs at the end portions of the trench gates causing insulation film deterioration
Solution Approach 1:
A boundary trench gate is introduced as an intermediary structure between the first trench gates and second trench gates. This boundary trench gate, which extends in a direction intersecting the trench gate extension direction and connects to the end portions of both first and second trenches, acts as a mediator to distribute and reduce electric field concentration at the interface between regions with different trench spacings, thereby preventing insulation film deterioration while maintaining avalanche breakdown resistance.
2Adaptability or versatility
If trench gates with different spacings are used in different regions, then device performance is optimized, but manufacturing complexity increases due to the need for precise trench formation and insulation film deposition
Solution Approach 1:
The device structure is segmented into distinct regions: a first diode region with first trench gates at a first spacing, a second diode region with second trench gates at a second spacing, and a boundary region with boundary trench gates. This segmentation allows each region to be independently optimized for its specific function while the boundary region provides a transition zone that manages the interface between regions with different parameters.
Solution Approach 2:
Different trench spacing configurations are applied to different regions based on their specific functional requirements. The first diode region uses a first spacing optimized for its operating conditions, the second diode region uses a second spacing optimized for its conditions, and the boundary region uses boundary trench gates with spacing optimized for electric field management at the interface.
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 suppresses electric field concentration at the end portions of the trench gates, thereby preventing insulation film deterioration and enhancing the semiconductor device's avalanche breakdown resistance.
Implementation Method 1
a trench electrode provided in a trench formed in a semiconductor substrate, with an insulation film therebetween, so that the trench electrode is opposed to the n− type drift layer, with the insulation film therebetween
Data Source
AI summary
A semiconductor device includes: first diode trench gates extending along a first main surface from a first end side of a cell region toward a second end side thereof opposite to the first end side, the first diode trench gates being disposed adjacent to each other at a first spacing; a boundary trench gate connected to end portions of the first diode trench gates and extending in a direction intersecting a direction of extension of the first diode trench gates; and second diode trench gates having end portions connected to the boundary trench gate and extending toward the second end side of the cell region.