Semiconductor Edge Structure for Voltage Proof
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Solution Overview
Problem
Semiconductor components, such as power transistors, face reduced maximum blocking voltage in the edge region due to the expansion of the space charge zone when a blocking voltage is applied, leading to a potential avalanche breakdown, which limits their voltage proof.
Innovation Solution
The implementation of an edge structure with trenches and edge electrodes, dielectric layers, and strategically doped edge zones in the semiconductor body to redirect electric field lines and increase the voltage proof in the edge region, allowing the avalanche breakdown to occur in the larger inner region instead of the edge region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the semiconductor component uses a conventional structure without edge termination, then the device complexity is low and manufacturing is simple, but the voltage proof in the edge region is reduced due to space charge zone expansion
Solution Approach 1:
The edge region is segmented into multiple zones with different doping concentrations (first edge zone with higher doping, second edge zone with lower doping). This segmentation allows the space charge zone to be distributed across multiple regions, preventing premature breakdown at the edge while maintaining manageable device complexity through a systematic approach to edge termination.
Solution Approach 2:
Different regions of the edge are assigned different doping qualities - the first edge zone has higher doping concentration to handle high field regions, while the second edge zone has lower doping concentration. This local differentiation of material properties optimizes voltage proof at each specific location without requiring complete redesign of the entire device structure.
2Reliability
If the doping concentration in the edge region is increased to improve voltage proof, then the maximum blocking voltage increases, but the space charge zone expansion is exacerbated leading to earlier avalanche breakdown
Solution Approach 1:
The edge region is divided into multiple doped zones with different doping concentrations. The first edge zone has higher doping to control field distribution, while the second edge zone has lower doping to limit space charge expansion. This segmentation allows the system to achieve high blocking voltage without excessive space charge zone width by distributing the electrical characteristics across multiple regions.
Solution Approach 2:
The doping concentration parameter is varied spatially across the edge region rather than being uniform. By changing the doping parameter from high in the first edge zone to low in the second edge zone, the patent optimizes both voltage proof and space charge zone management, achieving high blocking voltage without the detrimental effects of uniform high doping.
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 the voltage proof of the semiconductor component by distributing the blocking voltage more effectively across the semiconductor material, increasing the maximum blocking voltage and preventing premature avalanche breakdown in the edge region.
Implementation Method 1
starting from the semiconductor junction a space charge zone expands with increasing blocking voltage
Implementation Method 2
concentrate an avalanche breakdown in the larger inner region upon reaching a maximum blocking voltage
Implementation Method 3
a dielectric layer disposed in the trench between the edge electrode and the semiconductor body
Implementation Method 4
a first edge zone of the second conductivity type adjoining the trench and being at least partially disposed below the trench
Data Source
AI summary
A Semiconductor component having a space saving edge structure is disclosed. One embodiment provides a first side, a second side, an inner region, an edge region adjoining the inner region in a lateral direction of the semiconductor body, and a first semiconductor layer extending across the inner region and the edge region and having a basic doping of a first conductivity type. At least one active component zone of a second conductivity type, which is complementary to the first conductivity type, is disposed in the inner region in the first semiconductor layer. An edge structure is disposed in the edge region and includes at least one trench extending from the first side into the semiconductor body. An edge electrode is disposed in the trench, a dielectric layer is disposed in the trench between the edge electrode and the semiconductor body, a first edge zone of the second conductivity type adjoin the trench and are at least partially disposed below the trench.