Super Junction Pillar Layout for Peripheral Breakdown Stability
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Solution Overview
Problem
Conventional super junction semiconductor devices experience a decrease in breakdown voltage in the peripheral region due to a reverse recovery phenomenon, leading to potential curvature reduction and charge imbalance, which can cause damage before the active region reaches its breakdown voltage.
Innovation Solution
A super junction semiconductor device with a high concentration region surrounding the pillars in the peripheral region, having a horizontal width greater than the pillars in the transition region, and a doping concentration higher than the pillars, to increase the P/N dopant ratio and reduce the electric field magnitude, thereby suppressing the breakdown voltage decrease.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a reverse recovery layer is formed in the transition region to dissipate reverse recovery current, then reverse recovery phenomenon is suppressed, but the effective length of the N-type pillar is reduced
Solution Approach 1:
The patent applies local quality by forming a high concentration region specifically in the peripheral region with a horizontal width greater than that of pillars in the transition region. This localized structural modification addresses the reverse recovery issue in the peripheral region without affecting the N-type pillar length in the active region, thereby resolving the contradiction between suppressing reverse recovery and maintaining pillar effectiveness.
2Ease of manufacture
If the peripheral region is designed with standard doping, then manufacturing is simplified, but breakdown voltage decreases due to charge imbalance and reduced potential curvature
Solution Approach 1:
The patent applies parameter changes by modifying the doping concentration parameter in the peripheral region. A high concentration region is formed with a horizontal width greater than pillars in the transition region, which changes the electrical parameters (increases P/N dopant ratio) to enhance breakdown voltage and potential curvature while maintaining manufacturing feasibility through controlled doping processes.
3Reliability
If the horizontal width of high concentration region is increased, then breakdown voltage is enhanced, but device area increases
Solution Approach 1:
The patent applies local quality by precisely controlling the horizontal width of the high concentration region to be greater than pillars in the transition region but limited to the peripheral region. This localized approach enhances breakdown voltage through increased P/N dopant ratio without unnecessarily expanding the overall device area, as the high concentration region is confined to where it is most needed for suppressing reverse recovery and enhancing potential curvature.
Data Source
AI summary
A super junction semiconductor device includes a substrate of a first conductive type, an epitaxial layer disposed on the substrate, a plurality of pillars extending in a vertical direction and each being alternately arranged within the epitaxial layer, gate structures disposed on the epitaxial layer in the active region, a reverse recovery layer of a second conductive type, the reverse recovery layer disposed on both the pillars and the epitaxial layer and in the transition region to distribute a reverse recovery current, and at least one high concentration region surrounding an upper portion of at least one of the pillars in the peripheral region, the high concentration region having a horizontal width greater than that of one of the pillars provided in the transition region. Thus, a breakdown voltage may be inhibited from decreasing in the peripheral region.