Power Diode Termination Region with Variable Doping Pockets
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Solution Overview
Problem
High-voltage power diodes face inefficiencies due to stray electric fields causing undesired breakdowns and increased power dissipation, particularly in the edge regions, which existing designs struggle to mitigate effectively.
Innovation Solution
The power diode design incorporates a termination region with strategically placed pockets of varying doping concentrations to reduce electric fields and minimize power dissipation, featuring a frame-like arrangement of pockets surrounding the anode region, with specific doping concentrations and depths to enhance efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a termination region is provided in the wafer to block applied voltage, then voltage blocking capability is improved, but power dissipation increases due to stray electric fields in edge regions
Solution Approach 1:
The patent applies local quality by creating pockets with different doping concentrations (first doping concentration in first pocket, second doping concentration in second pockets) at specific locations within the termination region. This local variation in doping concentration allows different areas to have optimized electric field distribution, reducing peak electric fields at edge regions while maintaining voltage blocking capability, thereby reducing power dissipation without sacrificing reliability.
2Loss of energy
If the termination region width is reduced to improve device efficiency, then power dissipation decreases, but voltage blocking capability may be compromised
Solution Approach 1:
The patent changes the doping concentration parameter within the termination region by introducing pockets with first and second doping concentrations that differ from each other and from the base layer doping concentration. This parameter variation allows the termination region to maintain adequate width for voltage blocking while the localized high-doping pockets reduce peak electric fields, enabling reduced overall termination region width without compromising voltage blocking capability.
3Ease of manufacture
If uniform doping is used in the termination region to simplify manufacturing, then manufacturing complexity is reduced, but peak electric fields increase causing higher power dissipation
Solution Approach 1:
The patent implements local quality by introducing pockets with specific doping concentrations at defined locations (first pocket and second pockets surrounding the anode region) within the termination region. This localized doping variation targets the edge regions where peak electric fields occur, reducing power dissipation without requiring complex manufacturing across the entire device structure.
4Loss of energy
If the first pocket doping concentration is kept low to reduce electric fields, then power dissipation decreases, but the voltage blocking capability may be insufficient
Solution Approach 1:
The patent uses a composite doping structure where the termination region contains multiple pockets with different doping concentrations (first doping concentration in first pocket, second doping concentration in second pockets) embedded in the base layer material. This composite structure allows the first pocket to have lower doping concentration for electric field reduction while the second pockets provide additional voltage blocking support, achieving both reduced power dissipation and maintained voltage blocking capability through the combined effect of different doped regions.
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 effectively reduces peak electric fields and current densities, decreases power dissipation, and narrows the termination region width while maintaining voltage blocking capabilities, thereby improving the overall efficiency of high-voltage power diodes.
Implementation Method 1
this design effectively reduces peak electric fields and current densities
Implementation Method 2
the base layer comprises dopants, wherein the dopants are n-type dopants
Data Source
Figure 1~2
Figure 3~5
Figure 6~7
AI summary
A power diode (1) comprising a wafer having a cathode side (4) and an anode side (5) opposite to the cathode side (4) is provided, with - a base layer (2) of a first conductivity type, - an anode region (6) of a second conductivity type being different from the first conductivity type provided in the wafer at the anode side, and - a termination region (7) provided in the wafer between the cathode side (4) and the anode side (5), wherein - the termination region (7) surrounds the anode region (6) in lateral directions, - the termination region (7) comprises a first pocket (8) of the second conductivity type and at least two second pockets (9) of the second conductivity type, - the first pocket (8) is provided between the anode region (6) and the at least two second pockets (9) in lateral directions, and - the first pocket (8) has a first maximum doping concentration being smaller than a second maximum doping concentration of each of the at least two second pockets (9). Further, a method for producing a power diode (1) is provided.