Segmented JTE Field Relief Layout for Stable Breakdown Voltage
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Solution Overview
Problem
Semiconductor devices using junction termination extension (JTE) regions with field relief rings are susceptible to process variations, particularly due to the narrow width of innermost field relief rings, which can significantly impact breakdown voltage.
Innovation Solution
The use of separate field relief elements along the circumferential direction instead of closed rings allows for wider elements without exceeding a predefined electric field value, reducing susceptibility to process tolerances by increasing the number of PN junctions and diffusing majority charge carriers from more directions, thereby reducing the depletion region and maintaining a constant electrical field.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If field relief rings are used in the JTE region to spread the electrical field, then field crowding is prevented and breakdown voltage is improved, but the narrow width of innermost field relief rings makes the device highly susceptible to process variations and manufacturing tolerances
Solution Approach 1:
The patent divides the field relief function into multiple discrete field relief elements arranged in a circular pattern within the JTE region, rather than using continuous closed rings. This segmentation allows each element to be wider and more robust to manufacturing variations while collectively achieving the same field spreading effect. The segmented structure reduces sensitivity to lithography tolerances and process variations.
Solution Approach 2:
The patent applies different geometrical configurations to different regions of the JTE structure. The innermost field relief elements are designed with specific width and spacing characteristics optimized for their location, while outer elements have different dimensions. This local optimization allows each region to contribute effectively to field relief while maintaining manufacturing robustness.
2Manufacturing precision
If the width of field relief rings is increased to reduce susceptibility to process variations, then manufacturing precision is improved, but the electric field may exceed predefined values and breakdown voltage is compromised
Solution Approach 1:
By segmenting the field relief structure into multiple discrete elements arranged circularly, the patent enables each element to have sufficient width for manufacturing robustness without creating excessive electric field concentration. The distributed arrangement of segmented elements spreads the field relief function across multiple locations, preventing any single element from requiring excessive width that would compromise breakdown voltage.
Solution Approach 2:
The patent transitions from a two-dimensional ring structure to a three-dimensional arrangement of field relief elements with specific radial and circumferential positioning. This dimensional reorganization allows optimization of element width in the radial direction while maintaining appropriate spacing in the circumferential direction, achieving both manufacturing robustness and electrical performance.
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 design enhances the stability of semiconductor devices by reducing the impact of process variations on breakdown voltage and maintaining a consistent electrical field, making them less susceptible to manufacturing tolerances.
Implementation Method 1
diffusing majority charge carriers from more directions, thereby reducing the depletion region and maintaining a constant electrical field
Data Source
AI summary
A semiconductor device having an improved junction termination extension region is provided. The disclosure particularly relates to diodes having such an improved junction termination extension. The semiconductor device includes an active area extending in a first direction, and a junction termination extension, ‘JTE’, region of a first charge type surrounding the active area. The JTE region includes a plurality of field relief sub-regions that each surround the active area and that are mutually spaced apart in a direction perpendicular to a circumference of the active area. The plurality of field relief sub-regions includes a first group of field relief sub-regions, and for each field relief sub-region of the first group, a plurality of field relief elements of a second charge type is provided therein, which field relief elements are mutually spaced apart in a circumferential direction with respect to the active area.