Semiconductor Device Adjust Region for Breakdown Voltage
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Solution Overview
Problem
Conventional semiconductor devices with p-n junctions face limitations in breakdown voltage due to excessively high electric fields at high field points, leading to avalanche breakdown at voltages lower than the ideal breakdown voltage, which is not effectively addressed by existing junction termination extension (JTE) regions.
Innovation Solution
Incorporating an adjust region adjacent to the surface and between the termination extension region in semiconductor devices, which reduces peak electrical fields at breakdown voltages, allowing for improved blocking voltages and potentially reducing the length of the junction termination region while maintaining performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional p-n junction structure is used, then the device structure is simple, but the breakdown voltage is limited due to excessively high electric fields at high field points
Solution Approach 1:
The junction termination region is segmented into multiple doped regions with different doping concentrations. Specifically, a first doped region with higher concentration and a second doped region with lower concentration are created adjacent to the lightly doped region, forming a graded doping structure that divides the electric field distribution across multiple zones rather than concentrating it at a single interface.
Solution Approach 2:
Different regions of the junction termination are assigned different doping concentrations to optimize local electric field management. The first doped region has a higher doping concentration than the second doped region, creating a gradient that locally adjusts the electric field distribution. This local quality variation allows the structure to withstand higher reverse voltages by preventing excessive field concentration at any single point.
2Reliability
If a junction termination extension region is used to reduce high electric fields, then the breakdown voltage increases, but the device area increases
Solution Approach 1:
The doping concentration parameter is changed across different regions of the termination structure. By creating a graded doping profile where the first doped region has a higher concentration than the second doped region, the electric field distribution is optimized to achieve higher blocking voltages within a more compact area. This parameter variation allows efficient voltage blocking without requiring excessive lateral extension.
3Reliability
If the doping concentration is increased in the termination region to reduce electric fields, then the breakdown voltage improves, but the junction capacitance increases
Solution Approach 1:
The termination region is segmented into multiple doped regions with different doping concentrations rather than using a uniform high concentration. The first doped region has a higher concentration than the second doped region, creating a stepped or graded profile that reduces peak electric fields while minimizing the total dopant quantity required compared to a uniformly heavily doped structure.
Solution Approach 2:
Different local regions have different doping qualities optimized for their specific functions. The first doped region with higher concentration provides localized field reduction where needed, while the second doped region with lower concentration reduces overall dopant quantity. This local quality differentiation achieves reliable breakdown voltage without excessive total dopant content.
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
The introduction of an adjust region enhances the semiconductor device's ability to withstand reverse-blocking junction voltages by reducing peak electric fields and enabling reliable blocking voltages, while also potentially reducing the device's overall area.
Implementation Method 1
reduces peak electrical fields at breakdown voltages
Implementation Method 2
Avalanche breakdown occurs in such a device at a voltage substantially less than the ideal breakdown voltage because excessively high electric fields are present at certain locations
Data Source
AI summary
A semiconductor device includes a substrate comprising a semiconductor material. The substrate has a surface that defines a surface normal direction and includes a P-N junction comprising an interface between a first region and a second region, where the first (second) region includes a first (second) dopant type, so as to have a first (second) conductivity type. The substrate includes a termination extension region disposed adjacent to the P-N junction and having an effective concentration of the second dopant type that is generally the effective concentration of the second dopant type in the second doped region. The substrate includes an adjust region disposed adjacent to the surface and between the surface and at least part of the termination extension region, where the effective concentration of the second dopant type generally decreases when moving from the termination extension region into the adjust region along the surface normal direction.