Semiconductor Device Impurity Gradient Electric Field Control
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Solution Overview
Problem
Existing semiconductor devices with insulated gate bipolar transistors (IGBTs) and diodes face issues with electric field concentration near gate trenches and recovery current concentration in the deep region, which affects device performance.
Innovation Solution
A semiconductor device design with a deep p-type region that has varying p-type impurity concentration, higher on the voltage resistance side and lower near the body region, to suppress electric field concentration and recovery current concentration by controlling the p-type impurity distribution from the element range to the peripheral range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a deep region is provided at the boundary between element range and peripheral range to suppress electric field concentration, then electric field distribution is improved, but recovery current concentrates in the deep region causing performance degradation
Solution Approach 1:
The patent applies local quality by creating different impurity concentration zones within the deep region. The deep region is divided into a first deep region with higher p-type impurity concentration and a second deep region with lower p-type impurity concentration. This spatial variation in material properties allows the structure to simultaneously achieve electric field suppression (through the higher concentration zone) and recovery current dispersion (through the lower concentration zone), resolving the contradiction between these two opposing requirements.
Solution Approach 2:
The patent segments the deep region into multiple sub-regions with different impurity concentrations. By dividing the deep region into a first deep region (higher p-type impurity) and a second deep region (lower p-type impurity), the structure can perform multiple functions: the first deep region suppresses electric field concentration while the second deep region prevents recovery current concentration. This segmentation allows simultaneous optimization of both conflicting performance aspects.
2Reliability
If p-type impurity concentration is increased in the deep region to suppress electric field concentration, then electric field control is improved, but recovery current concentration in the deep region increases
Solution Approach 1:
The patent implements local quality by establishing a spatial gradient of p-type impurity concentration within the deep region. The first deep region has higher p-type impurity concentration for electric field control, while the second deep region has lower p-type impurity concentration to reduce recovery current concentration. This localized variation in material composition allows the structure to optimize both electric field control and device performance simultaneously, rather than using a uniform concentration that would compromise one or the other.
Solution Approach 2:
The patent applies parameter changes by varying the p-type impurity concentration parameter across different zones of the deep region. Instead of maintaining a constant impurity concentration, the patent creates a profile where concentration changes from the first deep region to the second deep region. This parameter variation enables the structure to achieve optimal electric field control in one zone while minimizing recovery current concentration in another zone, thereby improving overall device performance.
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 design effectively suppresses electric field concentration near the gate trenches and prevents recovery current from being concentrated in the deep region, enhancing the semiconductor device's performance and reliability.
Implementation Method 1
A p-type impurity concentration within the deep region is increased in a direction from the body region toward the voltage resistance region... an equipotential line is likely to extend in the lateral direction from the element region toward the voltage resistance region. Therefore, electric fields are suppressed from being concentrated near the gate trenches located at the end of the element region.
Implementation Method 2
since the p-type impurity concentration within the deep region is lower on the body region side, the resistance of the deep region located near the body region is higher. Accordingly, current is unlikely to flow through the deep region located near the body region. As a result, the recovery current is suppressed from being concentrated to the deep region.
Data Source
AI summary
A semiconductor device has a semiconductor substrate that includes an element range and a peripheral range. The semiconductor substrate includes: a body region disposed within the element range; a p-type deep region that is disposed from the element range through the peripheral range, is distributed from an upper surface of the semiconductor substrate to a position deeper than a lower end of each gate trench, and involves end gate trench; and a p-type voltage resistance region that is disposed within the peripheral range, and is distributed from the upper surface to a position shallower than a lower end of the p-type deep region. A p-type impurity concentration within the p-type deep region is increased in the direction from the body region toward the p-type voltage resistance region.