Buffer Region Doping Profile for Higher IGBT Breakdown Voltage
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Solution Overview
Problem
Existing semiconductor apparatuses face challenges in optimizing the doping concentration and hydrogen chemical concentration distributions in the buffer region, which affect the performance and reliability of components like IGBTs.
Innovation Solution
A semiconductor apparatus design with a specific doping concentration distribution in the buffer region, featuring a deepest slope from the lower surface to the upper surface, and a hydrogen chemical concentration distribution with distinct decrease portions and an intermediate uniform or peaked structure, enhancing the buffer region's functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the doping concentration in the buffer region is increased to improve breakdown voltage, then the breakdown voltage is improved, but the electric field strength increases which may cause other reliability issues
Solution Approach 1:
The patent applies local quality by creating different doping concentration regions within the buffer region. Specifically, it forms a first doping region with a first doping concentration and a second doping region with a second doping concentration that differs from the first. This allows different parts of the buffer region to have optimized local properties - some areas with higher doping for breakdown voltage and others with lower doping to control electric field strength, thereby resolving the contradiction between these two parameters.
Solution Approach 2:
The buffer region is segmented into multiple doping regions with different doping concentrations. The patent divides the buffer region into a first doping region and a second doping region, each with controlled doping concentrations. This segmentation allows independent optimization of different functional requirements within the same buffer region, enabling simultaneous improvement of breakdown voltage and control of electric field strength.
2Reliability
If the doping concentration distribution is optimized to improve device performance, then the manufacturing precision requirements increase
Solution Approach 1:
The patent employs preliminary action by forming the doping regions in a specific sequence during manufacturing. The first doping region is formed with a first doping concentration, and then the second doping region is formed with a second doping concentration. This staged approach allows each doping region to be independently controlled and optimized, reducing the overall manufacturing precision requirements compared to forming a uniform doping distribution in a single step.
Data Source
AI summary
Provided is a semiconductor apparatus, wherein a doping concentration distribution in the buffer region has a deepest slope where a doping concentration monotonically decreases to a position where it comes in contact with the drift region in a direction from the lower surface of the semiconductor substrate toward an upper surface, a hydrogen chemical concentration distribution in the buffer region includes in a first depth range provided with the slope: a first decrease portion where a hydrogen chemical concentration decreases toward the upper surface side; a second decrease portion located closer to the upper surface side than the first decrease portion is and where the chemical concentration decreases; and an intermediate portion arranged between the first and second decrease portions, and the intermediate portion has: a flat portion where the distribution is uniform; a peak in a slope of the chemical concentration; or a kink portion of the chemical concentration.