Semiconductor Device RBSOA Tolerance via Plug Region Doping
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Solution Overview
Problem
In semiconductor devices, particularly insulated gate bipolar transistors (IGBTs), miniaturization and sophistication lead to a reduction in Reverse Bias Safe Operating Area (RBSOA) tolerance, necessitating a solution to maintain or enhance this tolerance while achieving smaller dimensions.
Innovation Solution
The method involves forming a semiconductor device with trench portions, a contact region of a second conductivity type, an emitter region of a first conductivity type, and a plug region of the second conductivity type, where the plug region has a higher doping concentration than the contact region and is shallower in depth, with specific implantation depths and annealing temperatures to optimize the RBSOA tolerance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If miniaturization and sophistication are implemented in semiconductor devices, then device size is reduced and integration is improved, but RBSOA (Reverse Bias Safe Operating Area) tolerance decreases
Solution Approach 1:
The patent applies local quality by creating a plug region with higher doping concentration than the surrounding contact region. This localized high-doping area is positioned between the emitter region and the contact region, specifically in the region that will be in contact with the emitter electrode. The plug region has a doping concentration of 1×10^19 to 1×10^21 atoms/cm³, while the contact region has a lower doping concentration of 1×10^18 to 1×10^20 atoms/cm³. This local enhancement of doping concentration improves RBSOA tolerance without requiring overall device enlargement
Solution Approach 2:
The patent employs parameter changes by modifying the doping concentration parameter in a specific region. The plug region is formed with a doping concentration that is one to two orders of magnitude higher than the contact region. Additionally, the plug region is positioned at a shallower depth (peak position shallower than half the depth from upper surface to peak position of contact region doping concentration). These parameter changes in doping concentration and depth position enable improved RBSOA tolerance while maintaining miniaturized device dimensions
2Reliability
If the contact region is formed with sufficient doping concentration and depth, then electrical contact is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent applies preliminary action by forming the plug region with high doping concentration before the final contact hole formation and electrode deposition steps. The plug region is created through ion implantation of dopant at a first depth and first implantation amount, establishing a pre-formed high-doping region that simplifies subsequent processing. This preliminary doping action ensures good electrical contact without requiring complex multi-step doping sequences or adjustment procedures
Solution Approach 2:
The patent segments the contact structure into two distinct regions: the plug region with high doping concentration and the contact region with lower doping concentration. The plug region is positioned shallower than the contact region, with its peak doping concentration located at a depth shallower than half the depth from the upper surface to the peak position of the contact region. This segmentation allows each region to perform its specific function optimally while simplifying the overall manufacturing process through clear spatial and functional separation
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 approach effectively prevents a decrease in RBSOA tolerance, allowing for miniaturization and sophistication of semiconductor devices while maintaining or improving their operational safety and reliability.
Implementation Method 1
by implanting a dopant of the second conductivity type by a first depth and a first implantation amount
Implementation Method 2
The contact region may be annealed at a first temperature for a first period of time; and The plug region may be annealed at a second temperature for a second period of time
Data Source
AI summary
There is provided a method of manufacturing a semiconductor device including: forming a cell having a plurality of trench portions, a contact region, being formed by implanting a dopant of a second conductivity type by a first depth and a first implantation amount, and an emitter region, the cell having a length, which is smaller than or equal to a width between the trench portions, the emitter region, having a length, which is greater than a length of the contact region; forming a contact hole, having an opening width which is smaller than the length of the contact region; and forming a plug region by implanting the dopant of the second conductivity type by a second depth, being shallower than the first depth, and a second implantation amount, being greater than or equal to the first implantation amount, in the depth direction of the semiconductor substrate.