Power Semiconductor Edge Termination Segmentation
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Solution Overview
Problem
Conventional power semiconductor devices face challenges with low breakdown voltage due to uneven electric field lines and high thermal budget requirements for forming semiconductor pillars, leading to inefficient edge termination and increased leakage currents.
Innovation Solution
A power semiconductor device design featuring a substrate with an active portion and edge termination portion, including a first-type semiconductor region and spaced-apart second-type semiconductor segments, arranged to improve electric field distribution and reduce thermal processing needs, using multi-epitaxial techniques and varying doping concentrations to enhance breakdown voltage and minimize leakage currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the depletion area of the junction is increased by decreasing doping concentrations, then the electric field intensity decreases, but the breakdown voltage becomes low due to uneven electric field lines
Solution Approach 1:
The edge termination portion is segmented into a first-type semiconductor region and multiple spaced-apart second-type semiconductor segments. This segmentation creates multiple localized depletion areas that collectively provide uniform electric field distribution across the entire edge termination region, resolving the contradiction between depletion area size and electric field uniformity.
Solution Approach 2:
Different regions of the edge termination portion are given different doping concentrations and types (first-type vs. second-type segments). The second-type segments are strategically positioned to create localized high-field regions that balance the overall electric field distribution, allowing the junction to maintain both adequate depletion area and uniform electric field intensity for high breakdown voltage.
2Temperature
If the electric field intensity is increased by increasing doping concentrations, then the breakdown voltage remains low due to decreased depletion area
Solution Approach 1:
Instead of uniformly increasing doping concentration across the entire edge termination region, the invention segments the region into first-type and second-type semiconductor segments with different doping characteristics. This allows localized enhancement of electric field intensity in specific areas while maintaining adequate depletion area overall, thereby achieving high breakdown voltage.
Solution Approach 2:
The second-type semiconductor segments are positioned to create localized regions of higher doping concentration and electric field intensity, while the first-type regions maintain lower doping to preserve depletion area. This spatial variation in local quality enables simultaneous optimization of both electric field intensity and depletion area for high breakdown voltage performance.
3Ease of manufacture
If conventional thermal processes are used to form semiconductor pillars, then the thermal budget is relatively large, but this leads to increased manufacturing complexity and cost
Solution Approach 1:
The formation of the first-type semiconductor region and second-type semiconductor segments is merged into a single multi-epitaxial growth process. By combining what would traditionally require separate thermal processing steps into one continuous epitaxial sequence, the total thermal budget is reduced and manufacturing complexity is minimized while achieving the desired segmented structure.
Solution Approach 2:
The multi-epitaxial process serves multiple functions simultaneously: it forms both the first-type and second-type semiconductor regions, creates the segmented structure, and establishes the appropriate doping profiles all in one process step. This multi-functionality eliminates the need for multiple separate thermal processes, reducing both thermal budget and manufacturing complexity.
Data Source
AI summary
A power semiconductor device includes a substrate, a main body and an electrode unit. The main body includes an active portion, an edge termination portion surrounding the active portion, and an insulating layer disposed on the edge termination portion. The edge termination portion includes a first-type semiconductor region, and a plurality of spaced-apart second-type semiconductor segments distributed in the first-type semiconductor region and arranged at intervals along a Y-direction directing from the insulating layer toward the substrate, and an X-direction directing from the active portion toward the edge termination portion. The electrode unit includes a first electrode and a second electrode.