Semiconductor Field Limit Region with Low Concentration Zone
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The semiconductor layer is prone to breakdown due to electric field concentration in the field limit region, where the depletion layers from the field limit and active regions overlap, leading to inadequate relaxation of electric field strength.
Innovation Solution
A semiconductor device is designed with a second-conductivity-type low concentration region having a lower impurity concentration than the field limit region, formed along the peripheral edge of the field limit region on the opposite side to the active region, which expands the depletion layer in the opposite direction, thereby reducing electric field concentration and improving breakdown tolerance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a field limit region is formed to expand the depletion layer and improve withstand voltage, then the breakdown voltage is improved, but electric field concentration occurs in the field limit region causing semiconductor layer breakdown
Solution Approach 1:
The patent applies local quality by creating a low concentration region with specifically reduced impurity concentration (lower than the field limit region) at the peripheral edge opposite to the active region. This localized modification of impurity concentration distribution allows the depletion layer to extend further in that specific area, reducing electric field concentration at the field limit region while maintaining the overall field limiting function. The different impurity concentrations in different regions (active region, field limit region, and low concentration region) enable each region to perform its specific function optimally.
Solution Approach 2:
The patent changes the impurity concentration parameter by introducing a low concentration region where the impurity concentration is deliberately reduced compared to the field limit region. This parameter change (lower impurity concentration) allows the depletion layer to extend more widely in the low concentration region, thereby reducing electric field strength and preventing electric field concentration at the field limit region, while still maintaining adequate withstand voltage through the combined effect of all regions.
2Length of moving object
If the semiconductor layer thickness is reduced for miniaturization, then device size is reduced, but breakdown tolerance deteriorates
Solution Approach 1:
The patent applies local quality by creating a low concentration region with specifically reduced impurity concentration at the peripheral edge of the field limit region. This localized modification allows the depletion layer to extend further in that specific area, providing enhanced electric field relaxation capability. This enables the semiconductor layer to achieve adequate breakdown tolerance even with reduced overall thickness, as the low concentration region compensates for the reduced thickness by extending the depletion layer more effectively in the critical peripheral area.
3Device complexity
If the number of field limit regions is reduced for miniaturization, then device complexity is reduced, but electric field relaxation capability deteriorates
Solution Approach 1:
The patent changes the impurity concentration parameter by introducing a low concentration region with reduced impurity concentration adjacent to the field limit region. This parameter change enables a single field limit region to achieve better electric field relaxation capability, as the low concentration region extends the depletion layer more effectively. This compensates for reducing the number of field limit regions, allowing miniaturization while maintaining adequate electric field relaxation capability through the modified impurity concentration distribution.
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 electric field concentration at the field limit region, enhancing the semiconductor layer's breakdown tolerance and allowing for thinner layers or reduced number of field limit regions, facilitating miniaturization without compromising withstand voltage.
Implementation Method 1
The second-conductivity-type impurity concentration of the low concentration region is lower than the second-conductivity-type impurity concentration of the field limit region. Therefore, the depletion layer spreading from the low concentration region becomes larger than the depletion layer spreading from the field limit region.
Data Source
AI summary
A semiconductor device includes a semiconductor layer that has a main surface and that includes an active region, a first-conductivity-type first impurity region formed at a surface layer portion of the main surface of the semiconductor layer, a second-conductivity-type field limit region formed along a peripheral edge of the active region in a surface layer portion of the first impurity region, and a second-conductivity-type low concentration region that has a second-conductivity-type impurity concentration lower than a second-conductivity-type impurity concentration of the field limit region and that is formed along a peripheral edge of the field limit region in a region on a side opposite to the active region with respect to the field limit region in the surface layer portion of the first impurity region.