RC-IGBT Boundary Doping Layout for Lower Reverse Recovery Loss
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Solution Overview
Problem
In semiconductor devices, particularly RC-IGBTs, the reverse recovery process is hindered by excessive hole injection from the IGBT region to the diode region, leading to increased reverse recovery peak current and loss, which existing technologies fail to adequately address.
Innovation Solution
The semiconductor device incorporates a semiconductor substrate with a diode portion featuring an anode region with a lower doping concentration in the second boundary region and a base region with a lower doping concentration in the first boundary region, along with a trench contact portion and plug region, to suppress hole injection during reverse recovery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a high concentration P type layer is formed in the IGBT region, then the on-state voltage is reduced, but excessive hole injection occurs to the diode region during reverse recovery
Solution Approach 1:
The patent applies local quality by creating a boundary region with distinct doping characteristics between the IGBT region and diode region. The P type layer in the boundary region has a lower concentration than in the IGBT region, while the IGBT region maintains high concentration for low on-state voltage. This spatial variation in doping concentration allows the IGBT region to achieve low on-state voltage while the boundary region suppresses hole injection into the diode region during reverse recovery.
2Object-generated harmful factors
If the doping concentration in the boundary region is reduced, then hole injection is suppressed, but the breakdown withstand capability may be compromised
Solution Approach 1:
The patent applies parameter changes by carefully controlling the doping concentration gradient across different regions. The P type layer concentration is varied spatially: high in the IGBT region for low on-state voltage, and lower in the boundary region to suppress hole injection while maintaining adequate breakdown withstand capability. The specific concentration range (1×10^16 to 1×10^18 atoms/cm³) in the boundary region is optimized to balance hole injection suppression with breakdown voltage requirements.
Data Source
AI summary
A semiconductor device includes a semiconductor substrate that has a transistor portion and a diode portion and that is provided with a plurality of trench portions, in which the transistor portion has a main region that has the emitter region and the contact region at the front surface of the semiconductor substrate and that is spaced apart from the diode portion and a first boundary region that is provided between the main region and the diode portion and that has, at the front surface of the semiconductor substrate, the emitter region and the base region which are alternately provided in a trench extension direction.