Semiconductor Drift Region Doping Layout for Breakdown and ON-Resistance
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Solution Overview
Problem
Existing semiconductor devices struggle to simultaneously increase breakdown voltage and reduce ON-resistance, as uniform n-type impurity concentration in the drift region either increases resistance or decreases breakdown voltage.
Innovation Solution
The semiconductor device incorporates a n−-type drift region with multiple first regions and a second region, where the n-type impurity concentration is higher in the first regions than in the second region, allowing for easier depletion in specific directions while maintaining low resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If uniform n-type impurity concentration is used in the drift region, then manufacturing is simplified, but breakdown voltage decreases and ON-resistance increases
Solution Approach 1:
The drift region is divided into multiple regions with different n-type impurity concentrations: a first region with concentration ND1, a second region with concentration ND2, and a third region with concentration ND3, where ND1 < ND2 < ND3. This local differentiation allows the high-concentration third region to provide low ON-resistance while the low-concentration first region ensures complete depletion and high breakdown voltage, resolving the contradiction between manufacturing simplicity and device performance.
2Device complexity
If uniform n-type impurity concentration is used in the drift region, then device structure is simplified, but ON-resistance increases
Solution Approach 1:
The drift region employs a multi-zone impurity concentration structure with three distinct regions (first, second, and third regions) having progressively increasing n-type impurity concentrations. The third region with the highest concentration (ND3) provides low ON-resistance by facilitating carrier conduction, while the overall graduated structure maintains manageable device complexity through systematic spatial variation rather than uniform composition.
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 increases breakdown voltage by ensuring complete depletion of the drift region in critical directions while reducing ON-resistance by optimizing impurity concentration gradients.
Implementation Method 1
a cross section of the n−-type drift region includes a plurality of first regions provided respectively around the plurality of second electrodes in the second direction and the third direction, and a second region provided around the first regions. Impurity concentrations of the first conductivity type in the first regions are higher than an impurity concentration of the first conductivity type in the second region.
Implementation Method 2
This design effectively increases breakdown voltage by ensuring complete depletion of the drift region in critical directions while reducing ON-resistance by optimizing impurity concentration gradients.
Data Source
AI summary
According to one embodiment, a semiconductor device includes a first electrode, a first semiconductor region of a first conductivity type, a second electrode, a gate electrode, second semiconductor regions of a second conductivity type, third semiconductor regions of the first conductivity type, and a third electrode. The second electrode is provided in a plurality in second and third directions. Each second electrode opposes a portion of the first semiconductor region in the second and third directions with an insulating layer interposed. The gate electrode is provided around each second electrode. The first semiconductor region includes first regions provided respectively around the second electrodes and the second region provided around the first regions in the second and third directions. Impurity concentration of the first conductivity type in each of the first regions is higher than impurity concentration of the first conductivity type in the second region.