Guard Ring Diffusion Layout for Higher Terminal Breakdown Voltage
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Solution Overview
Problem
Existing semiconductor devices struggle to achieve high breakdown voltage in the terminal region of the semiconductor substrate.
Innovation Solution
The semiconductor device incorporates multiple guard rings and first diffusion regions in the terminal region, with the first diffusion regions having a wider width than the guard rings, allowing for closer spacing and enhanced depletion layer spread.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple guard rings and diffusion regions are arranged in the terminal region, then the breakdown voltage is improved, but the device complexity increases
Solution Approach 1:
The terminal region is segmented into multiple guard rings and multiple first diffusion regions, which are arranged in a coordinated pattern. This segmentation allows the depletion layer to be distributed and spread more effectively across the terminal region, thereby improving breakdown voltage while maintaining a systematic and manageable structure.
Solution Approach 2:
The guard rings and first diffusion regions are nested within each other in a concentric arrangement around the element region. Each guard ring is positioned within the boundaries of corresponding first diffusion regions, creating a nested structure that maximizes the use of space and enhances the depletion layer spread without excessive complexity.
2Reliability
If the width of first diffusion regions is increased, then the depletion layer spread is enhanced, but the manufacturing precision requirements increase
Solution Approach 1:
The first diffusion regions are designed with locally optimized widths that are larger than those of the guard rings, specifically in the radial direction from the element region. This local quality enhancement allows the depletion layer to spread more widely in critical areas while maintaining tighter dimensional control in other regions, thereby balancing reliability improvement with manufacturing feasibility.
3Reliability
If multiple guard rings and diffusion regions are formed separately, then the breakdown voltage is improved, but the manufacturing cost increases
Solution Approach 1:
The formation of multiple guard rings and multiple first diffusion regions is merged into a single ion implantation process step. By using a common mask pattern that defines both the guard rings and the first diffusion regions, the patent enables simultaneous formation of all these structures in one process, thereby reducing manufacturing complexity and cost while achieving the desired breakdown voltage improvement.
Solution Approach 2:
The common mask used in the ion implantation process serves multiple functions: it defines the positions of guard rings, defines the positions of first diffusion regions, and controls the spatial relationship between them. This multi-functionality of the mask simplifies the manufacturing process and reduces the number of separate steps required, thereby lowering production costs.
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 results in a higher breakdown voltage for the terminal region by allowing the depletion layer to spread more widely, while also enabling cost-effective manufacturing through the use of a common mask for forming the guard rings and diffusion regions.
Implementation Method 1
forming multiple guard rings of p-type at positions exposed on the one main surface of the semiconductor substrate by implanting p-type impurity ions through the mask, and forming multiple first diffusion regions at a first depth from the one main surface of the semiconductor substrate by implanting p-type impurity ions through the mask
Data Source
AI summary
A semiconductor device includes a semiconductor substrate having an element region and a terminal region located around the element region. The terminal region includes multiple guard rings and multiple first diffusion regions. When the semiconductor substrate is viewed in a plan view, one of the first diffusion regions is arranged correspondingly to one of the guard rings, and each of the guard rings is located in corresponding one of the first diffusion regions. A width of each of the first diffusion regions is larger than a width of corresponding one of the guard rings.