Semiconductor Device with Localized Anode Doping for Conduction Optimization
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Solution Overview
Problem
Conventional RC-IGBTs face challenges in optimizing the conduction characteristics of both the transistor and diode portions, particularly in reverse recovery tolerance, due to limitations in doping concentration and carrier extraction efficiency.
Innovation Solution
The semiconductor device incorporates a diode portion with an anode region of lower doping concentration and a first high concentration region, which is in contact with the anode region and has a higher doping concentration than the anode region, allowing for improved conduction characteristics and reduced switching loss, while maintaining optimal reverse recovery tolerance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the doping concentration of the anode region is increased to improve conduction characteristics, then the forward voltage of the diode portion is reduced, but the reverse recovery tolerance deteriorates
Solution Approach 1:
The patent applies local quality by creating a non-uniform doping concentration distribution within the anode region. Specifically, it introduces a high doping concentration region adjacent to the first well region with a doping concentration of 1×10^19 to 1×10^21 atoms/cm³, while the other portions of the anode region maintain a lower doping concentration of 1×10^17 to 1×10^19 atoms/cm³. This localized high doping concentration improves carrier extraction at the critical interface, reducing forward voltage, while the lower doping concentration in other areas preserves reverse recovery tolerance.
Solution Approach 2:
The patent changes the doping concentration parameter spatially within the anode region. By establishing two distinct doping concentration zones (high concentration near the well region, lower concentration elsewhere), it optimizes both conduction characteristics and reverse recovery behavior. The high doping concentration region enhances carrier extraction efficiency to reduce forward voltage drop, while the lower doping concentration in other portions prevents excessive carrier storage that would degrade reverse recovery tolerance.
2Ease of manufacture
If the doping concentration is uniform throughout the anode region, then manufacturing is simplified, but conduction characteristics and reverse recovery tolerance cannot be independently optimized
Solution Approach 1:
The patent implements local quality by specifying different doping concentrations for different regions of the anode. The region adjacent to the first well region has a doping concentration of 1×10^19 to 1×10^21 atoms/cm³, while other portions have 1×10^17 to 1×10^19 atoms/cm³. This spatial variation in doping concentration enables independent optimization of conduction characteristics (through the high concentration region) and reverse recovery tolerance (through the lower concentration regions), while still being manufacturable through selective implantation processes.
Data Source
AI summary
To provide a semiconductor device having excellent conduction characteristics of a transistor portion and a diode portion. The semiconductor device having a transistor portion and a diode portion, the semiconductor device includes: a drift region of a first conductivity type provided on a semiconductor substrate, a first well region of a second conductivity type provided on an upper surface side of the semiconductor substrate, an anode region of the second conductivity provided on the upper surface side of the semiconductor substrate, in the diode portion, and a first high concentration region of a second conductivity type which is provided in contact with a first well region between the anode region and the first well region, and has a higher doping concentration than the anode region.