Semiconductor Trench Termination With Local Dielectric Thickness Control
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Solution Overview
Problem
Existing semiconductor devices face challenges in achieving high breakdown voltage while maintaining low on-resistance and efficient processing, as known field termination configurations often compromise die area, processing costs, and performance characteristics.
Innovation Solution
The semiconductor device incorporates a trench with varying dielectric thickness in the termination and active regions, optimizing trench depths, pitches, and doping levels to distribute electric fields uniformly, thereby increasing breakdown voltage and reducing on-resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a thicker dielectric is used in the termination region trench, then breakdown voltage is increased, but device area and processing complexity increase
Solution Approach 1:
The patent applies local quality by implementing a non-uniform dielectric thickness distribution within the trench structure. The dielectric layer is thicker in the termination region (providing higher breakdown voltage) and thinner in the active region (reducing processing complexity and device area). This spatially varying property resolves the contradiction by optimizing each region's dielectric thickness according to its specific functional requirements.
2Reliability
If trench depth is increased to improve breakdown voltage, then manufacturing difficulty and cost increase
Solution Approach 1:
The patent implements local quality through spatially varying trench depths across different regions. The termination region features deeper trenches for enhanced breakdown voltage, while the active region has shallower trenches that are easier to manufacture. This regional differentiation resolves the contradiction between achieving high breakdown voltage and maintaining ease of manufacture.
3Productivity
If mesa width is reduced to increase device density, then electric field distribution and breakdown characteristics deteriorate
Solution Approach 1:
The patent applies local quality by implementing different mesa width specifications for different regions. The active region mesas can be narrower to achieve high device density, while the termination region mesas are optimized for proper electric field distribution and breakdown characteristics. This regional differentiation allows simultaneous achievement of high productivity and reliability.
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 enhances breakdown voltage, reduces on-resistance by approximately 50%, and improves processing efficiency with a 20% decrease in mesa region width between devices, maintaining reliability and performance.
Implementation Method 1
optimize trench depths, pitches, and doping levels to distribute electric fields uniformly, thereby increasing breakdown voltage
Implementation Method 2
a dielectric lining a bottom portion of the trench where the dielectric has a first portion disposed in the termination region and a second portion disposed in the active region, the first portion of the dielectric having a vertical thickness greater than a vertical thickness of the second portion of the dielectric
Data Source
Figure 1A~1B
Figure 2
Figure 3A
AI summary
In one general aspect, an apparatus can include a semiconductor region, and a trench defined within the semiconductor region. The trench can have a depth aligned along a vertical axis and have a length aligned along a longitudinal axis orthogonal to the vertical axis. The trench can have a first portion of the length included in a termination region of the semiconductor region and can have a second portion of the length included in an active region of the semiconductor region. A dielectric lines a bottom portion of the trench, the dielectric having a first portion disposed in the termination region of the semiconductor region and a second portion disposed in the active region of the semiconductor region, the first portion of the dielectric disposed in the termination region having a vertical thickness different than a vertical thickness of the second portion of the dielectric disposed in the active region.