Lateral Semiconductor Device Resistive Field Plate Impurity Gradient
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Solution Overview
Problem
Existing semiconductor devices with lateral elements, such as lateral diodes and IGBTs, face variations in breakdown voltage due to the resistance and impurity concentration of the scroll-shaped field plate (SRFP), leading to non-uniform electric field gradients and reduced reliability.
Innovation Solution
A semiconductor device with a lateral element is designed, featuring a resistive field plate with a specific impurity concentration of 1×10^18 cm^-3 at its second end portion and a resistance of 1×10^6 Ω/sq or less, which maintains a uniform potential gradient and reduces breakdown voltage variations by limiting depletion areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a scroll-shaped field plate (SRFP) is used to reduce electric field in a lateral high-voltage element, then the breakdown voltage can be achieved for direct current and low speed switching application, but the resistance of the SRFP causes variation in breakdown voltage due to impurity concentration non-uniformity
Solution Approach 1:
The patent applies local quality by creating a multi-zone impurity concentration structure within the field plate region. Specifically, it forms a first impurity region with a first concentration, a second impurity region with a second concentration, and a third impurity region with a third concentration. This non-uniform impurity distribution optimizes the electric field characteristics locally in different regions, reducing breakdown voltage variation while maintaining the required breakdown voltage strength.
Solution Approach 2:
The patent changes the impurity concentration parameter across different regions of the field plate. By systematically varying the impurity concentration from the first region through the second region to the third region, the patent optimizes the electrical characteristics to reduce breakdown voltage variation while maintaining the required breakdown voltage level for reliable operation.
2Reliability
If the impurity concentration in the SRFP is increased to reduce resistance, then the breakdown voltage stability improves, but the manufacturing precision becomes more difficult to control
Solution Approach 1:
The patent segments the field plate impurity concentration into distinct regions with different concentration levels. Instead of attempting to achieve uniform high precision impurity concentration throughout the entire field plate, the patent divides it into multiple zones (first, second, and third impurity regions) with progressively varying concentrations. This segmentation makes the manufacturing process more controllable while achieving the desired electrical characteristics.
Solution Approach 2:
The patent applies local quality by creating a multi-zone impurity concentration structure within the field plate region. Specifically, it forms a first impurity region with a first concentration, a second impurity region with a second concentration, and a third impurity region with a third concentration. This non-uniform impurity distribution optimizes the electric field characteristics locally in different regions, reducing breakdown voltage variation while maintaining the required breakdown voltage strength.
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 solution effectively stabilizes the breakdown voltage and improves the reliability of lateral IGBTs and FWDs by ensuring uniform electric field gradients and reducing the impact of impurity concentration variations, enhancing their operational performance and durability.
Implementation Method 1
the breakdown voltage can vary depending on the concentration of an impurity in the SRFP and the resistance of the SRFP
Implementation Method 2
a uniform potential gradient and reduces breakdown voltage variations by limiting depletion areas
Data Source
AI summary
A semiconductor device with a lateral element includes a semiconductor substrate, first and second electrodes on the substrate, and a resistive field plate extending from the first electrode to the second electrode. The lateral element passes a current between the first and second electrodes. A voltage applied to the second electrode is less than a voltage applied to the first electrode. The resistive field plate has a first end portion and a second end portion opposite to the first end portion. The second end portion is located closer to the second electrode than the first end portion. An impurity concentration in the second end portion is equal to or greater than 1×1018 cm−3.